Apache Tomcat: HTTP/2 DoS via malformed request

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-78437
StatePUBLISHED
Assignerapache
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-23 12:17:07 UTC
Updated2026-09-23 19:19:21 UTC
DescriptionIncomplete 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.

Risk And Classification

Primary CVSS: v3.1 7.3 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS: 0.002600000 probability, percentile 0.156860000 (date 2026-09-24)

Problem Types: CWE-459 | CWE-459 CWE-459 Incomplete cleanup

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apache Software Foundation Apache Tomcat affected 11.0.19 11.0.25 semver Not specified
CNA Apache Software Foundation Apache Tomcat affected 10.1.53 10.1.59 semver Not specified
CNA Apache Software Foundation Apache Tomcat affected 9.0.116 9.0.121 semver Not specified
CNA Apache Software Foundation Apache Tomcat unaffected 8.5.100 semver Not specified

References

ReferenceSourceLinkTags
www.openwall.com/lists/oss-security/2026/09/23/26 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
lists.apache.org/thread/qkmsos3s8chn5053qr466rzwv6sk5gjg [email protected] lists.apache.org
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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