GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-26304 (GCVE-0-2026-26304)

Vulnerability from cvelistv5 – Published: 2026-03-16 19:53 – Updated: 2026-03-17 13:38
VLAI
Title
Permission Bypass in Playbook Run Creation
Summary
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542
Severity
4.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-17 13:37 UTC
CWE
  • CWE-863 - Incorrect Authorization
Assigner
References
URL Tags
https://mattermost.com/security-updates vendor-advisory
Impacted products
Vendor Product Version CPE status
Mattermost Mattermost Affected: 11.3.0 , ≤ 11.3.0 (semver)
Affected: 11.2.0 , ≤ 11.2.2 (semver)
Unaffected: 11.4.0
Unaffected: 11.3.1
Unaffected: 11.2.3
guessed Create a notification for this product.
Credits
0x7oda7123
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-26304",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-17T13:37:56.844126Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-17T13:38:03.996Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Mattermost",
          "vendor": "Mattermost",
          "versions": [
            {
              "lessThanOrEqual": "11.3.0",
              "status": "affected",
              "version": "11.3.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "11.2.2",
              "status": "affected",
              "version": "11.2.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "11.4.0"
            },
            {
              "status": "unaffected",
              "version": "11.3.1"
            },
            {
              "status": "unaffected",
              "version": "11.2.3"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "0x7oda7123"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Mattermost versions 11.3.x \u003c= 11.3.0, 11.2.x \u003c= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
            "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": "2026-03-16T19:53:21.650Z",
        "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "shortName": "Mattermost"
      },
      "references": [
        {
          "name": "MMSA-2025-00542",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://mattermost.com/security-updates"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3 or higher."
        }
      ],
      "source": {
        "advisory": "MMSA-2025-00542",
        "defect": [
          "https://mattermost.atlassian.net/browse/MM-66248"
        ],
        "discovery": "EXTERNAL"
      },
      "title": "Permission Bypass in Playbook Run Creation"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
    "assignerShortName": "Mattermost",
    "cveId": "CVE-2026-26304",
    "datePublished": "2026-03-16T19:53:21.650Z",
    "dateReserved": "2026-02-13T10:43:14.474Z",
    "dateUpdated": "2026-03-17T13:38:03.996Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-26304",
      "date": "2026-09-17",
      "epss": "0.00159",
      "percentile": "0.05458"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-26304\",\"sourceIdentifier\":\"responsibledisclosure@mattermost.com\",\"published\":\"2026-03-16T20:16:17.730\",\"lastModified\":\"2026-06-17T10:26:03.473\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Mattermost versions 11.3.x \u003c= 11.3.0, 11.2.x \u003c= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542\"},{\"lang\":\"es\",\"value\":\"Las versiones de Mattermost 11.3.x \u0026lt;= 11.3.0, 11.2.x \u0026lt;= 11.2.2 no verifican el permiso run_create para un playbookId vac\u00edo, lo que permite a los miembros del equipo crear ejecuciones no autorizadas a trav\u00e9s de la API de ejecuci\u00f3n de playbooks. ID de Aviso de Mattermost: MMSA-2025-00542\"}],\"affected\":[{\"source\":\"responsibledisclosure@mattermost.com\",\"affectedData\":[{\"vendor\":\"Mattermost\",\"product\":\"Mattermost\",\"defaultStatus\":\"unaffected\",\"versions\":[{\"version\":\"11.3.0\",\"lessThanOrEqual\":\"11.3.0\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"11.2.0\",\"lessThanOrEqual\":\"11.2.2\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"11.4.0\",\"status\":\"unaffected\"},{\"version\":\"11.3.1\",\"status\":\"unaffected\"},{\"version\":\"11.2.3\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"responsibledisclosure@mattermost.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N\",\"baseScore\":4.3,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.8,\"impactScore\":1.4}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-03-17T13:37:56.844126Z\",\"id\":\"CVE-2026-26304\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"responsibledisclosure@mattermost.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-863\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"11.2.0\",\"versionEndExcluding\":\"11.2.3\",\"matchCriteriaId\":\"7F64C167-943D-4F3F-9374-BCC8DECB3881\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"11.3.0\",\"versionEndExcluding\":\"11.3.1\",\"matchCriteriaId\":\"945A6E29-209F-4992-8692-BEF63DCB6B98\"}]}]}],\"references\":[{\"url\":\"https://mattermost.com/security-updates\",\"source\":\"responsibledisclosure@mattermost.com\",\"tags\":[\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "current_release_date": "2026-03-27T07:58:09+00:00",
      "cve": "CVE-2026-26304",
      "id": "CVE-2026-26304",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "Permission Bypass in Playbook Run Creation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26304.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-03-31T08:32:00Z",
      "cve": "CVE-2026-26304",
      "id": "CVE-2026-26304",
      "initial_release_date": "2026-03-28T00:28:27Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-26304",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-26304.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-26304\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-17T13:37:56.844126Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-03-17T13:38:00.683Z\"}}], \"cna\": {\"title\": \"Permission Bypass in Playbook Run Creation\", \"source\": {\"defect\": [\"https://mattermost.atlassian.net/browse/MM-66248\"], \"advisory\": \"MMSA-2025-00542\", \"discovery\": \"EXTERNAL\"}, \"credits\": [{\"lang\": \"en\", \"type\": \"finder\", \"value\": \"0x7oda7123\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 4.3, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"NONE\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"Mattermost\", \"product\": \"Mattermost\", \"versions\": [{\"status\": \"affected\", \"version\": \"11.3.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.3.0\"}, {\"status\": \"affected\", \"version\": \"11.2.0\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"11.2.2\"}, {\"status\": \"unaffected\", \"version\": \"11.4.0\"}, {\"status\": \"unaffected\", \"version\": \"11.3.1\"}, {\"status\": \"unaffected\", \"version\": \"11.2.3\"}], \"defaultStatus\": \"unaffected\"}], \"solutions\": [{\"lang\": \"en\", \"value\": \"Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3 or higher.\"}], \"references\": [{\"url\": \"https://mattermost.com/security-updates\", \"name\": \"MMSA-2025-00542\", \"tags\": [\"vendor-advisory\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Mattermost versions 11.3.x \u003c= 11.3.0, 11.2.x \u003c= 11.2.2 fail to verify run_create permission for empty playbookId, which allows team members to create unauthorized runs via the playbook run API. Mattermost Advisory ID: MMSA-2025-00542\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-863\", \"description\": \"CWE-863: Incorrect Authorization\"}]}], \"providerMetadata\": {\"orgId\": \"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee\", \"shortName\": \"Mattermost\", \"dateUpdated\": \"2026-03-16T19:53:21.650Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-26304\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-03-17T13:38:03.996Z\", \"dateReserved\": \"2026-02-13T10:43:14.474Z\", \"assignerOrgId\": \"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee\", \"datePublished\": \"2026-03-16T19:53:21.650Z\", \"assignerShortName\": \"Mattermost\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.