CVE-2026-78437 (GCVE-0-2026-78437)
Vulnerability from cvelistv5 – Published: 2026-09-23 11:26 – Updated: 2026-09-23 18:10
VLAI
EPSS
VEX
Title
Apache Tomcat: HTTP/2 DoS via malformed request
Summary
Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
Severity
7.3 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-23 16:25 UTC
CWE
- CWE-459 - Incomplete cleanup
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://lists.apache.org/thread/qkmsos3s8chn5053q… | vendor-advisory |
| http://www.openwall.com/lists/oss-security/2026/0… |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Apache Software Foundation | Apache Tomcat |
Affected:
11.0.19 , ≤ 11.0.25
(semver)
Affected: 10.1.53 , ≤ 10.1.59 (semver) Affected: 9.0.116 , ≤ 9.0.121 (semver) Unaffected: 0 , ≤ 8.5.100 (semver) |
guessed |
{
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 7.3,
"baseSeverity": "HIGH",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-78437",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-23T16:25:38.365317Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-09-23T16:25:54.815Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
},
{
"providerMetadata": {
"dateUpdated": "2026-09-23T18:10:46.744Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"url": "http://www.openwall.com/lists/oss-security/2026/09/23/26"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Apache Tomcat",
"vendor": "Apache Software Foundation",
"versions": [
{
"lessThanOrEqual": "11.0.25",
"status": "affected",
"version": "11.0.19",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.1.59",
"status": "affected",
"version": "10.1.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "9.0.121",
"status": "affected",
"version": "9.0.116",
"versionType": "semver"
},
{
"lessThanOrEqual": "8.5.100",
"status": "unaffected",
"version": "0",
"versionType": "semver"
}
]
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eIncomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.\u003c/p\u003e\u003cp\u003eThis issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.\u003c/p\u003e\u003cp\u003eUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.\u003c/p\u003e"
}
],
"value": "Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.\n\n\n\nUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue."
}
],
"metrics": [
{
"other": {
"content": {
"text": "low"
},
"type": "Textual description of severity"
},
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-459",
"description": "CWE-459 Incomplete cleanup",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-23T11:26:29.362Z",
"orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
"shortName": "apache"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://lists.apache.org/thread/qkmsos3s8chn5053qr466rzwv6sk5gjg"
}
],
"source": {
"discovery": "INTERNAL"
},
"title": "Apache Tomcat: HTTP/2 DoS via malformed request",
"x_generator": {
"engine": "Vulnogram 1.0.3"
}
}
},
"cveMetadata": {
"assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
"assignerShortName": "apache",
"cveId": "CVE-2026-78437",
"datePublished": "2026-09-23T11:26:29.362Z",
"dateReserved": "2026-08-24T16:10:49.885Z",
"dateUpdated": "2026-09-23T18:10:46.744Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Apache Tomcat",
"vendor": "Apache Software Foundation",
"versions": [
{
"lessThanOrEqual": "11.0.25",
"status": "affected",
"version": "11.0.19",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.1.59",
"status": "affected",
"version": "10.1.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "9.0.121",
"status": "affected",
"version": "9.0.116",
"versionType": "semver"
},
{
"lessThanOrEqual": "8.5.100",
"status": "unaffected",
"version": "0",
"versionType": "semver"
}
]
}
],
"source": "security@apache.org"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.\n\n\n\nUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue."
}
],
"id": "CVE-2026-78437",
"lastModified": "2026-09-23T19:19:21.640",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 7.3,
"baseSeverity": "HIGH",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.4,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-78437",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-23T16:25:38.365317Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-23T12:17:07.340",
"references": [
{
"source": "security@apache.org",
"url": "https://lists.apache.org/thread/qkmsos3s8chn5053qr466rzwv6sk5gjg"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "http://www.openwall.com/lists/oss-security/2026/09/23/26"
}
],
"sourceIdentifier": "security@apache.org",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-459"
}
],
"source": "security@apache.org",
"type": "Secondary"
}
]
}
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 7.3,
"baseSeverity": "HIGH",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-78437",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-23T16:25:38.365317Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-09-23T16:25:28.259Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Apache Tomcat",
"vendor": "Apache Software Foundation",
"versions": [
{
"lessThanOrEqual": "11.0.25",
"status": "affected",
"version": "11.0.19",
"versionType": "semver"
},
{
"lessThanOrEqual": "10.1.59",
"status": "affected",
"version": "10.1.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "9.0.121",
"status": "affected",
"version": "9.0.116",
"versionType": "semver"
},
{
"lessThanOrEqual": "8.5.100",
"status": "unaffected",
"version": "0",
"versionType": "semver"
}
]
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eIncomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.\u003c/p\u003e\u003cp\u003eThis issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.\u003c/p\u003e\u003cp\u003eUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.\u003c/p\u003e"
}
],
"value": "Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.\n\n\n\nThis issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.\n\n\n\nUsers are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue."
}
],
"metrics": [
{
"other": {
"content": {
"text": "low"
},
"type": "Textual description of severity"
},
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-459",
"description": "CWE-459 Incomplete cleanup",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-23T11:26:29.362Z",
"orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
"shortName": "apache"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://lists.apache.org/thread/qkmsos3s8chn5053qr466rzwv6sk5gjg"
}
],
"source": {
"discovery": "INTERNAL"
},
"title": "Apache Tomcat: HTTP/2 DoS via malformed request",
"x_generator": {
"engine": "Vulnogram 1.0.3"
}
}
},
"cveMetadata": {
"assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
"assignerShortName": "apache",
"cveId": "CVE-2026-78437",
"datePublished": "2026-09-23T11:26:29.362Z",
"dateReserved": "2026-08-24T16:10:49.885Z",
"dateUpdated": "2026-09-23T16:25:54.815Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
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.
Loading…