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592 vulnerabilities by mattermost
CVE-2026-6062 (GCVE-0-2026-6062)
Vulnerability from cvelistv5 – Published: 2026-06-22 13:40 – Updated: 2026-06-22 13:40
VLAI
Title
IDOR in Jira plugin subscription edit endpoint
Summary
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT request to the subscription edit endpoint.. Mattermost Advisory ID: MMSA-2026-00650
Severity
6.4 (Medium)
CWE
- CWE-639 - Authorization Bypass Through User-Controlled Key
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.7.0 , ≤ 11.7.0
(semver)
Affected: 11.6.0 , ≤ 11.6.2 (semver) Affected: 11.5.0 , ≤ 11.5.5 (semver) Affected: 10.11.0 , ≤ 10.11.17 (semver) Unaffected: 11.8.0 Unaffected: 11.7.1 Unaffected: 11.6.3 Unaffected: 11.5.6 Unaffected: 10.11.18 |
Credits
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Mattermost",
"vendor": "Mattermost",
"versions": [
{
"lessThanOrEqual": "11.7.0",
"status": "affected",
"version": "11.7.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.6.2",
"status": "affected",
"version": "11.6.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.5.5",
"status": "affected",
"version": "11.5.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.11.17",
"status": "affected",
"version": "10.11.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "11.8.0"
},
{
"status": "unaffected",
"version": "11.7.1"
},
{
"status": "unaffected",
"version": "11.6.3"
},
{
"status": "unaffected",
"version": "11.5.6"
},
{
"status": "unaffected",
"version": "10.11.18"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "0hmz"
}
],
"descriptions": [
{
"lang": "en",
"value": "Mattermost versions 11.7.x \u003c= 11.7.0, 11.6.x \u003c= 11.6.2, 11.5.x \u003c= 11.5.5, 10.11.x \u003c= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT request to the subscription edit endpoint.. Mattermost Advisory ID: MMSA-2026-00650"
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 6.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-639",
"description": "CWE-639: Authorization Bypass Through User-Controlled Key",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-22T13:40:07.776Z",
"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
"shortName": "Mattermost"
},
"references": [
{
"name": "MMSA-2026-00650",
"tags": [
"vendor-advisory"
],
"url": "https://mattermost.com/security-updates"
}
],
"solutions": [
{
"lang": "en",
"value": "Update Mattermost to versions 11.8.0, 11.7.1, 11.6.3, 11.5.6, 10.11.18 or higher."
}
],
"source": {
"advisory": "MMSA-2026-00650",
"defect": [
"https://mattermost.atlassian.net/browse/MM-68271"
],
"discovery": "EXTERNAL"
},
"title": "IDOR in Jira plugin subscription edit endpoint",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
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"assignerShortName": "Mattermost",
"cveId": "CVE-2026-6062",
"datePublished": "2026-06-22T13:40:07.776Z",
"dateReserved": "2026-04-10T10:57:59.278Z",
"dateUpdated": "2026-06-22T13:40:07.776Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-6673 (GCVE-0-2026-6673)
Vulnerability from cvelistv5 – Published: 2026-06-22 13:38 – Updated: 2026-06-22 13:38
VLAI
Title
Mattermost Jira plugin had unauthenticated {{/ac/installed}} lifecycle callback during pending Jira Cloud install
Summary
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to /ac/installed during the pending-install window.. Mattermost Advisory ID: MMSA-2026-00654
Severity
6.4 (Medium)
CWE
- CWE-306 - Missing Authentication for Critical Function
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.7.0 , ≤ 11.7.0
(semver)
Affected: 11.6.0 , ≤ 11.6.2 (semver) Affected: 11.5.0 , ≤ 11.5.5 (semver) Affected: 10.11.0 , ≤ 10.11.17 (semver) Unaffected: 11.8.0 Unaffected: 11.7.1 Unaffected: 11.6.3 Unaffected: 11.5.6 Unaffected: 10.11.18 |
Credits
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Mattermost",
"vendor": "Mattermost",
"versions": [
{
"lessThanOrEqual": "11.7.0",
"status": "affected",
"version": "11.7.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.6.2",
"status": "affected",
"version": "11.6.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.5.5",
"status": "affected",
"version": "11.5.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.11.17",
"status": "affected",
"version": "10.11.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "11.8.0"
},
{
"status": "unaffected",
"version": "11.7.1"
},
{
"status": "unaffected",
"version": "11.6.3"
},
{
"status": "unaffected",
"version": "11.5.6"
},
{
"status": "unaffected",
"version": "10.11.18"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "insomnia1102"
}
],
"descriptions": [
{
"lang": "en",
"value": "Mattermost versions 11.7.x \u003c= 11.7.0, 11.6.x \u003c= 11.6.2, 11.5.x \u003c= 11.5.5, 10.11.x \u003c= 10.11.17 fail to authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret and disrupt the Jira integration via POST to /ac/installed during the pending-install window.. Mattermost Advisory ID: MMSA-2026-00654"
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 6.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:H",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-306",
"description": "CWE-306: Missing Authentication for Critical Function",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-22T13:38:56.594Z",
"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
"shortName": "Mattermost"
},
"references": [
{
"name": "MMSA-2026-00654",
"tags": [
"vendor-advisory"
],
"url": "https://mattermost.com/security-updates"
}
],
"solutions": [
{
"lang": "en",
"value": "Update Mattermost to versions 11.8.0, 11.7.1, 11.6.3, 11.5.6, 10.11.18 or higher."
}
],
"source": {
"advisory": "MMSA-2026-00654",
"defect": [
"https://mattermost.atlassian.net/browse/MM-68376"
],
"discovery": "EXTERNAL"
},
"title": "Mattermost Jira plugin had unauthenticated {{/ac/installed}} lifecycle callback during pending Jira Cloud install",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
"assignerShortName": "Mattermost",
"cveId": "CVE-2026-6673",
"datePublished": "2026-06-22T13:38:56.594Z",
"dateReserved": "2026-04-20T13:45:33.430Z",
"dateUpdated": "2026-06-22T13:38:56.594Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-8074 (GCVE-0-2026-8074)
Vulnerability from cvelistv5 – Published: 2026-06-22 13:37 – Updated: 2026-06-22 13:37
VLAI
Title
Improper Permission Check Allows User Manager to Deactivate Bot Accounts
Summary
Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to enforce bot-specific permission checks on the user active status endpoint, which allows a User Manager with user management write access but no Integrations access to deactivate bot accounts via the PUT /api/v4/users/{id}/active API endpoint.. Mattermost Advisory ID: MMSA-2026-00667
Severity
CWE
- CWE-863 - Incorrect Authorization
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.7.0 , ≤ 11.7.0
(semver)
Affected: 10.11.0 , ≤ 10.11.17 (semver) Unaffected: 11.8.0 Unaffected: 11.7.1 Unaffected: 10.11.18 |
Credits
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Mattermost",
"vendor": "Mattermost",
"versions": [
{
"lessThanOrEqual": "11.7.0",
"status": "affected",
"version": "11.7.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.11.17",
"status": "affected",
"version": "10.11.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "11.8.0"
},
{
"status": "unaffected",
"version": "11.7.1"
},
{
"status": "unaffected",
"version": "10.11.18"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "hackit_bharat"
}
],
"descriptions": [
{
"lang": "en",
"value": "Mattermost versions 11.7.x \u003c= 11.7.0, 10.11.x \u003c= 10.11.17 fail to enforce bot-specific permission checks on the user active status endpoint, which allows a User Manager with user management write access but no Integrations access to deactivate bot accounts via the PUT /api/v4/users/{id}/active API endpoint.. Mattermost Advisory ID: MMSA-2026-00667"
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 3.8,
"baseSeverity": "LOW",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "HIGH",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-863",
"description": "CWE-863: Incorrect Authorization",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-22T13:37:44.617Z",
"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
"shortName": "Mattermost"
},
"references": [
{
"name": "MMSA-2026-00667",
"tags": [
"vendor-advisory"
],
"url": "https://mattermost.com/security-updates"
}
],
"solutions": [
{
"lang": "en",
"value": "Update Mattermost to versions 11.8.0, 11.7.1, 10.11.18 or higher."
}
],
"source": {
"advisory": "MMSA-2026-00667",
"defect": [
"https://mattermost.atlassian.net/browse/MM-68685"
],
"discovery": "EXTERNAL"
},
"title": "Improper Permission Check Allows User Manager to Deactivate Bot Accounts",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
"assignerShortName": "Mattermost",
"cveId": "CVE-2026-8074",
"datePublished": "2026-06-22T13:37:44.617Z",
"dateReserved": "2026-05-07T10:55:28.977Z",
"dateUpdated": "2026-06-22T13:37:44.617Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-9162 (GCVE-0-2026-9162)
Vulnerability from cvelistv5 – Published: 2026-06-22 13:36 – Updated: 2026-06-22 13:36
VLAI
Title
Global session revocation does not invalidate active WebSocket connections
Summary
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to invalidate cached authentication state for active WebSocket connections during global session revocation, which allows a user with an existing WebSocket connection to remain authenticated and continue receiving real-time events until the cached session expires or the client reconnects.. Mattermost Advisory ID: MMSA-2026-00664
Severity
4.3 (Medium)
CWE
- CWE-613 - Insufficient Session Expiration
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.7.0 , ≤ 11.7.0
(semver)
Affected: 11.6.0 , ≤ 11.6.2 (semver) Affected: 11.5.0 , ≤ 11.5.5 (semver) Affected: 10.11.0 , ≤ 10.11.17 (semver) Unaffected: 11.8.0 Unaffected: 11.7.1 Unaffected: 11.6.3 Unaffected: 11.5.6 Unaffected: 10.11.18 |
Credits
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Mattermost",
"vendor": "Mattermost",
"versions": [
{
"lessThanOrEqual": "11.7.0",
"status": "affected",
"version": "11.7.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.6.2",
"status": "affected",
"version": "11.6.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.5.5",
"status": "affected",
"version": "11.5.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.11.17",
"status": "affected",
"version": "10.11.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "11.8.0"
},
{
"status": "unaffected",
"version": "11.7.1"
},
{
"status": "unaffected",
"version": "11.6.3"
},
{
"status": "unaffected",
"version": "11.5.6"
},
{
"status": "unaffected",
"version": "10.11.18"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "winfunc"
}
],
"descriptions": [
{
"lang": "en",
"value": "Mattermost versions 11.7.x \u003c= 11.7.0, 11.6.x \u003c= 11.6.2, 11.5.x \u003c= 11.5.5, 10.11.x \u003c= 10.11.17 fail to invalidate cached authentication state for active WebSocket connections during global session revocation, which allows a user with an existing WebSocket connection to remain authenticated and continue receiving real-time events until the cached session expires or the client reconnects.. Mattermost Advisory ID: MMSA-2026-00664"
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 4.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-613",
"description": "CWE-613: Insufficient Session Expiration",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-06-22T13:36:43.998Z",
"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
"shortName": "Mattermost"
},
"references": [
{
"name": "MMSA-2026-00664",
"tags": [
"vendor-advisory"
],
"url": "https://mattermost.com/security-updates"
}
],
"solutions": [
{
"lang": "en",
"value": "Update Mattermost to versions 11.8.0, 11.7.1, 11.6.3, 11.5.6, 10.11.18 or higher."
}
],
"source": {
"advisory": "MMSA-2026-00664",
"defect": [
"https://mattermost.atlassian.net/browse/MM-68542"
],
"discovery": "EXTERNAL"
},
"title": "Global session revocation does not invalidate active WebSocket connections",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
"assignerShortName": "Mattermost",
"cveId": "CVE-2026-9162",
"datePublished": "2026-06-22T13:36:43.998Z",
"dateReserved": "2026-05-21T11:17:28.560Z",
"dateUpdated": "2026-06-22T13:36:43.998Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-5139 (GCVE-0-2026-5139)
Vulnerability from cvelistv5 – Published: 2026-06-22 13:34 – Updated: 2026-06-22 13:34
VLAI
Title
GitLab Plugin Allows Non-Admin Users to Modify Default Instance Configuration
Summary
Mattermost versions 11.7.x <= 11.7.0, 11.6.x <= 11.6.2, 11.5.x <= 11.5.5, 10.11.x <= 10.11.17 fail to enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler, which allows any authenticated user to overwrite the global default GitLab instance configuration via the {{/gitlab connect <instance-name>}} slash command.. Mattermost Advisory ID: MMSA-2026-00644
Severity
5.4 (Medium)
CWE
- CWE-862 - Missing Authorization
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.7.0 , ≤ 11.7.0
(semver)
Affected: 11.6.0 , ≤ 11.6.2 (semver) Affected: 11.5.0 , ≤ 11.5.5 (semver) Affected: 10.11.0 , ≤ 10.11.17 (semver) Unaffected: 11.8.0 Unaffected: 11.7.1 Unaffected: 11.6.3 Unaffected: 11.5.6 Unaffected: 10.11.18 |
Credits
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Mattermost",
"vendor": "Mattermost",
"versions": [
{
"lessThanOrEqual": "11.7.0",
"status": "affected",
"version": "11.7.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.6.2",
"status": "affected",
"version": "11.6.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "11.5.5",
"status": "affected",
"version": "11.5.0",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.11.17",
"status": "affected",
"version": "10.11.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "11.8.0"
},
{
"status": "unaffected",
"version": "11.7.1"
},
{
"status": "unaffected",
"version": "11.6.3"
},
{
"status": "unaffected",
"version": "11.5.6"
},
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CVE-2026-8683 (GCVE-0-2026-8683)
Vulnerability from cvelistv5 – Published: 2026-06-15 14:06 – Updated: 2026-06-15 16:06
VLAI
Title
Overly long URLs crash the Mattermost Desktop App
Summary
Mattermost Desktop App versions <=6.1 5.5.13.0 fail to account for attempting to open extremely long URLs in the Mattermost Desktop App which allows a malicious server owner to crash the application via including a script to call window.open on a very large URL. Mattermost Advisory ID: MMSA-2026-00652
Severity
6.5 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
0 , ≤ 5.5.13
(semver)
Unaffected: 6.2.0 Unaffected: 5.13.6.0 |
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CVE-2026-6517 (GCVE-0-2026-6517)
Vulnerability from cvelistv5 – Published: 2026-06-15 13:55 – Updated: 2026-06-15 16:00
VLAI
Title
Mattermost Desktop App fails to restrict the allow list of domains which NTLM credentials are passed
Summary
Mattermost Desktop App versions <=6.1 5.5.13.0 fail to restrict the allow list of domains to which NTLM credentials were forwarded to in the Mattermost Desktop App which allows any user on a server without the image proxy enabled to intercept other users credentials via embedding an image that routes to an external web server. Mattermost Advisory ID: MMSA-2026-00651
Severity
6.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-522 - Insufficiently Protected Credentials
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
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Affected:
0 , ≤ 5.5.13
(semver)
Unaffected: 6.2.0 Unaffected: 5.13.6.0 |
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CVE-2026-6961 (GCVE-0-2026-6961)
Vulnerability from cvelistv5 – Published: 2026-06-12 15:56 – Updated: 2026-06-16 13:17
VLAI
Title
CVE-2026-6961: Path traversal via unsanitized FileInfo.Name in Mattermost federation sync
Summary
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field.. Mattermost Advisory ID: MMSA-2026-00661
Severity
7.6 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.1
(semver)
Affected: 11.5.0 , ≤ 11.5.4 (semver) Affected: 10.11.0 , ≤ 10.11.15 (semver) Affected: 10.11.0 , ≤ 10.11.16 (semver) Unaffected: 11.7.0 Unaffected: 11.6.2 Unaffected: 11.5.5 Unaffected: 10.11.16 Unaffected: 10.11.17 |
Credits
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CVE-2026-7387 (GCVE-0-2026-7387)
Vulnerability from cvelistv5 – Published: 2026-06-12 15:54 – Updated: 2026-06-13 03:56
VLAI
Title
Mattermost group syncable endpoints allow privilege escalation via scheme_admin
Summary
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselves and group members to team or channel admin via crafted API requests.. Mattermost Advisory ID: MMSA-2026-00665
Severity
8.8 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-863 - Incorrect Authorization
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.1
(semver)
Affected: 11.5.0 , ≤ 11.5.4 (semver) Affected: 10.11.0 , ≤ 10.11.15 (semver) Affected: 10.11.0 , ≤ 10.11.16 (semver) Unaffected: 11.7.0 Unaffected: 11.6.2 Unaffected: 11.5.5 Unaffected: 10.11.16 Unaffected: 10.11.17 |
Credits
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CVE-2026-6046 (GCVE-0-2026-6046)
Vulnerability from cvelistv5 – Published: 2026-06-12 15:52 – Updated: 2026-06-12 17:18
VLAI
Title
Plugin bot username conflict allows user account to be used as bot identity in Mattermost Server
Summary
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to validate that a username returned during bot registration belongs to a bot account, which allows an unprivileged attacker to intercept private messages sent by plugins via direct message channels by pre-registering a user account with a predictable plugin bot username.. Mattermost Advisory ID: MMSA-2026-00649
Severity
5.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.1
(semver)
Affected: 11.5.0 , ≤ 11.5.4 (semver) Affected: 10.11.0 , ≤ 10.11.15 (semver) Affected: 10.11.0 , ≤ 10.11.16 (semver) Unaffected: 11.7.0 Unaffected: 11.6.2 Unaffected: 11.5.5 Unaffected: 10.11.16 Unaffected: 10.11.17 |
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CVE-2026-6689 (GCVE-0-2026-6689)
Vulnerability from cvelistv5 – Published: 2026-06-12 15:51 – Updated: 2026-06-12 17:18
VLAI
Title
*Missing* {{invite_user}} *permission check on team creation allows unprivileged users to set open-invite and allowed-domains team settings*
Summary
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Fail to enforce PermissionInviteUser when setting AllowOpenInvite or AllowedDomains during team creation (the check was only applied on update/patch), which allows an authenticated user holding PermissionCreateTeam but not PermissionInviteUser on the resulting team to configure invite-controlled team settings (make the team publicly joinable via open invite and/or constrain membership via allowed domains) that they are not permitted to set on an existing team via POST /api/v4/teams with allow_open_invite: true and/or a non-empty allowed_domains in the request body.. Mattermost Advisory ID: MMSA-2026-00655
Severity
4.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-862 - Missing Authorization
Assigner
References
1 reference
| URL | Tags |
|---|---|
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Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
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Affected:
11.6.0 , ≤ 11.6.1
(semver)
Affected: 11.5.0 , ≤ 11.5.4 (semver) Affected: 10.11.0 , ≤ 10.11.15 (semver) Affected: 10.11.0 , ≤ 10.11.16 (semver) Unaffected: 11.7.0 Unaffected: 11.6.2 Unaffected: 11.5.5 Unaffected: 10.11.16 Unaffected: 10.11.17 |
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CVE-2026-7184 (GCVE-0-2026-7184)
Vulnerability from cvelistv5 – Published: 2026-06-12 15:49 – Updated: 2026-06-12 17:19
VLAI
Title
Mattermost Remote Cluster PATCH API Leaks Authentication Tokens
Summary
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the {{manage_secure_connections}} permission to obtain remote cluster authentication tokens via a PATCH request to the remote cluster endpoint.. Mattermost Advisory ID: MMSA-2026-00662
Severity
6.5 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-201 - Insertion of Sensitive Information Into Sent Data
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.1
(semver)
Affected: 11.5.0 , ≤ 11.5.4 (semver) Affected: 10.11.0 , ≤ 10.11.15 (semver) Unaffected: 11.7.0 Unaffected: 11.6.2 Unaffected: 11.5.5 Unaffected: 10.11.17 |
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CVE-2026-6739 (GCVE-0-2026-6739)
Vulnerability from cvelistv5 – Published: 2026-06-12 15:49 – Updated: 2026-06-13 03:56
VLAI
Title
Mattermost: Delegated admins could patch protected default system roles
Summary
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API.. Mattermost Advisory ID: MMSA-2026-00656
Severity
6.7 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-863 - Incorrect Authorization
Assigner
References
1 reference
| URL | Tags |
|---|---|
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Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
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Affected:
11.6.0 , ≤ 11.6.1
(semver)
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CVE-2026-3433 (GCVE-0-2026-3433)
Vulnerability from cvelistv5 – Published: 2026-06-12 15:46 – Updated: 2026-06-12 17:19
VLAI
Title
Mattermost fails to scope role_updated websocket events to authorized team and channel members
Summary
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to restrict role_updated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change notifications for private teams they are not a member of via the websocket connection.. Mattermost Advisory ID: MMSA-2026-00616
Severity
4.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.1
(semver)
Affected: 11.5.0 , ≤ 11.5.4 (semver) Affected: 10.11.0 , ≤ 10.11.15 (semver) Affected: 10.11.0 , ≤ 10.11.16 (semver) Unaffected: 11.7.0 Unaffected: 11.6.2 Unaffected: 11.5.5 Unaffected: 10.11.16 Unaffected: 10.11.17 |
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CVE-2026-6957 (GCVE-0-2026-6957)
Vulnerability from cvelistv5 – Published: 2026-05-27 14:23 – Updated: 2026-05-28 03:55
VLAI
Title
Path traversal in Mattermost Legal Hold plugin via unsanitized file name from federated peer allows arbitrary file write.
Summary
Mattermost Plugins versions <=1.1.5 fail to sanitize filenames received from federated peers before using them to construct export destination paths, which allows an administrator of a remote federated Mattermost server to write files to arbitrary locations within the target server's filestore via a malicious filename delivered through the shared-channel attachment sync protocol. Mattermost Advisory ID: MMSA-2026-00659
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
0 , ≤ 1.1.5
(semver)
Unaffected: .0 |
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CVE-2026-4915 (GCVE-0-2026-4915)
Vulnerability from cvelistv5 – Published: 2026-05-25 07:10 – Updated: 2026-05-26 14:43
VLAI
Title
Server panic via outgoing webhook responses
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to filter nil elements from outgoing webhook attachment payloads before processing, which allows an authenticated user to cause a denial of service (server process termination) via a crafted webhook callback response containing a null attachment entry.. Mattermost Advisory ID: MMSA-2026-00641
Severity
6.5 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-754 - Improper Check for Unusual or Exceptional Conditions
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
Credits
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CVE-2026-28735 (GCVE-0-2026-28735)
Vulnerability from cvelistv5 – Published: 2026-05-22 16:26 – Updated: 2026-05-22 16:56
VLAI
Title
GitHub OAuth Scope Validation
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the OAuth token scope on the callback which allows an authenticated Mattermost user to gain access to private repositories via modifying the scope parameter in the GitHub authorization URL.. Mattermost Advisory ID: MMSA-2026-00628
Severity
5.4 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-863 - Incorrect Authorization
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
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CVE-2026-4635 (GCVE-0-2026-4635)
Vulnerability from cvelistv5 – Published: 2026-05-22 10:28 – Updated: 2026-05-22 12:06
VLAI
Title
Persistent notification timing attack causing server denial of service
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting existing persistent notifications and archiving the channel.. Mattermost Advisory ID: MMSA-2026-00637
Severity
6.5 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
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CVE-2026-3473 (GCVE-0-2026-3473)
Vulnerability from cvelistv5 – Published: 2026-05-22 10:27 – Updated: 2026-05-22 12:12
VLAI
Title
Improper file ownership validation in the Boards API allows unauthorised file access
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate file ownership and access control, which allows an authenticated user to access and download files belonging to other users or teams via crafted Boards API requests using valid file IDs.. Mattermost Advisory ID: MMSA-2026-00620
Severity
5.9 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-639 - Authorization Bypass Through User-Controlled Key
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
Credits
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CVE-2026-4646 (GCVE-0-2026-4646)
Vulnerability from cvelistv5 – Published: 2026-05-22 10:25 – Updated: 2026-05-22 12:13
VLAI
Title
Insufficient input validation in GitHub plugin API causes denial of service
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate user-supplied input in API request handlers which allows an authenticated attacker to crash the plugin process via a crafted HTTP request to the PR details endpoint.. Mattermost Advisory ID: MMSA-2026-00638
Severity
4.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-1287 - Improper Validation of Specified Type of Input
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
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CVE-2026-3636 (GCVE-0-2026-3636)
Vulnerability from cvelistv5 – Published: 2026-05-22 10:23 – Updated: 2026-05-22 12:13
VLAI
Title
Sanitize team member data returned by API
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to sanitize team member data when returned via API to users without elevated permissions which allows a user without permissions to get data about team members roles via invoking various team API endpoints.. Mattermost Advisory ID: MMSA-2026-00626
Severity
4.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
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CVE-2026-5740 (GCVE-0-2026-5740)
Vulnerability from cvelistv5 – Published: 2026-05-22 10:22 – Updated: 2026-05-22 12:14
VLAI
Title
Unauthenticated WebSocket binary frame causes denial of service in Mattermost Server
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to properly validate msgpack-encoded WebSocket frames before memory allocation which allows an unauthenticated remote attacker to crash the server process and cause a full service outage for all users via a crafted binary WebSocket message sent to the public WebSocket endpoint.. Mattermost Advisory ID: MMSA-2026-00647
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-789 - Memory Allocation with Excessive Size Value
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
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CVE-2026-5308 (GCVE-0-2026-5308)
Vulnerability from cvelistv5 – Published: 2026-05-22 10:20 – Updated: 2026-05-22 12:14
VLAI
Title
Missing request body size limits on Zoom plugin HTTP endpoints
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646
Severity
4.9 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-400 - Uncontrolled Resource Consumption
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
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CVE-2026-5755 (GCVE-0-2026-5755)
Vulnerability from cvelistv5 – Published: 2026-05-22 10:18 – Updated: 2026-05-22 12:15
VLAI
Title
Denial of service via crafted TIFF file upload
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.2, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service (server OOM) via uploading a crafted TIFF file or posting a URL that serves one.. Mattermost Advisory ID: MMSA-2026-00648
Severity
6.5 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-400 - Uncontrolled Resource Consumption
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
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Affected:
11.6.0 , ≤ 11.6.0
(semver)
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CVE-2026-22880 (GCVE-0-2026-22880)
Vulnerability from cvelistv5 – Published: 2026-05-21 08:22 – Updated: 2026-05-21 12:39
VLAI
Title
Mobile SSO authentication flow allows credential theft via malicious server
Summary
Mattermost Mobile Apps versions <=2.37 11.4 2.0.37 11.0.4 11.1.3 11.3.2 10.11.11.0 fail to properly validate the SSO authentication callback origin which allows an attacker controlling a malicious Mattermost server to steal user credentials for a legitimate Mattermost server via relaying the SSO code exchange flow through the mobile application. Mattermost Advisory ID: MMSA-2025-00564
Severity
6.1 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-352 - Cross-Site Request Forgery (CSRF)
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
0 , ≤ 2.0.37
(semver)
Affected: 0 , ≤ 11.0.4 (semver) Affected: 0 , ≤ 11.1.3 (semver) Affected: 0 , ≤ 11.3.2 (semver) Affected: 0 , ≤ 10.11.11 (semver) Unaffected: 2.38.0 Unaffected: 11.5.0 Unaffected: 2.37.1.0 Unaffected: 11.4.1 Unaffected: 11.3.2 Unaffected: 11.2.4 Unaffected: 10.11.12 |
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CVE-2026-4858 (GCVE-0-2026-4858)
Vulnerability from cvelistv5 – Published: 2026-05-21 08:12 – Updated: 2026-05-22 03:55
VLAI
Title
Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
Summary
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to check integration URL for path traversal which allows an malicious authenticated user to call an arbitrary API via system admin Mattermost auth token using via path traversal in integration action URL.. Mattermost Advisory ID: MMSA-2026-00640
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Assigner
References
1 reference
| URL | Tags |
|---|---|
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Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
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Affected:
11.6.0 , ≤ 11.6.0
(semver)
Affected: 11.5.0 , ≤ 11.5.3 (semver) Affected: 11.4.0 , ≤ 11.4.4 (semver) Affected: 10.11.0 , ≤ 10.11.14 (semver) Unaffected: 11.7.0 Unaffected: 11.6.1 Unaffected: 11.5.4 Unaffected: 11.4.5 Unaffected: 10.11.15 |
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CVE-2026-4055 (GCVE-0-2026-4055)
Vulnerability from cvelistv5 – Published: 2026-05-21 07:13 – Updated: 2026-05-21 12:39
VLAI
Title
Insufficient permission validation on cross-team playbook run creation
Summary
Mattermost versions 11.5.x <= 11.5.1 fail to validate team-level run_create permission against the target team when creating a playbook run which allows an authenticated team member to create runs in teams where they lack permission via specifying a different team ID in the run creation API request. Mattermost Advisory ID: MMSA-2026-00629
Severity
4.3 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-863 - Incorrect Authorization
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.5.0 , ≤ 11.5.1
(semver)
Unaffected: 11.6.0 Unaffected: 11.5.2 Unaffected: 10.11.14 Unaffected: 11.4.4 |
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CVE-2026-3471 (GCVE-0-2026-3471)
Vulnerability from cvelistv5 – Published: 2026-05-18 08:45 – Updated: 2026-05-18 14:35
VLAI
Title
Opening a window with {{javascript:alert()}} as URL causes crash in the Mattermost Desktop App
Summary
Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent an invalid URL from loading in a pop-up window in the Mattermost Desktop App which allows a malicious server owner to repeated crash the application via calling {{window.open('javascript:alert()');}}. Mattermost Advisory ID: MMSA-2026-00618
Severity
6.5 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-939 - Improper Authorization in Handler for Custom URL Scheme
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
0 , ≤ 6.0.1
(semver)
Affected: 0 , ≤ 5.4.13 (semver) Unaffected: 6.2.0 Unaffected: 6.1.1.0 Unaffected: 5.13.5.0 |
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CVE-2026-4643 (GCVE-0-2026-4643)
Vulnerability from cvelistv5 – Published: 2026-05-18 08:43 – Updated: 2026-05-18 14:36
VLAI
Title
Calling window.close() from server-side content causes crash in the Mattermost Desktop App
Summary
Mattermost Desktop App versions <=6.1 6.0.1 5.4.13.0 fail to prevent server-rendered content from closing an underlying application view in the Mattermost Desktop App which allows a malicious server or plugin to crash the desktop client via invoking {{window.close()}} in the renderer context, leading to a denial of service condition at the client level. Mattermost Advisory ID: MMSA-2026-00633
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-754 - Improper Check for Unusual or Exceptional Conditions
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://mattermost.com/security-updates | vendor-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
0 , ≤ 6.0.1
(semver)
Affected: 0 , ≤ 5.4.13 (semver) Unaffected: 6.2.0 Unaffected: 6.1.1.0 Unaffected: 5.13.5.0 |
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CVE-2026-6333 (GCVE-0-2026-6333)
Vulnerability from cvelistv5 – Published: 2026-05-18 08:41 – Updated: 2026-05-19 17:19
VLAI
Title
SSRF via Host Header Spoofing in Custom Slash Commands
Summary
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost Advisory ID: MMSA-2026-00582
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
References
1 reference
| URL | Tags |
|---|---|
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Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| Mattermost | Mattermost |
Affected:
11.5.0 , ≤ 11.5.1
(semver)
Affected: 10.11.0 , ≤ 10.11.13 (semver) Unaffected: 11.6.0 Unaffected: 11.5.2 Unaffected: 10.11.14 |
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