Apache Tomcat Denial of Service via invalid HTTP priority header

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.6 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U · score source

EPSS

• CVE-2025-31650: 61.32% estimated exploitation activity in the next 30 days; percentile 99.17 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Improper Input Validation vulnerability in Apache Tomcat. Incorrect error handling for some invalid HTTP priority headers resulted in incomplete clean-up of the failed request which created a memory leak. A large number of such requests could trigger an OutOfMemoryException resulting in a denial of service. This issue affects Apache Tomcat: from 9.0.76 through 9.0.102, from 10.1.10 through 10.1.39, from 11.0.0-M2 through 11.0.5. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.90 though 8.5.100. Users are recommended to upgrade to version 9.0.104, 10.1.40 or 11.0.6 which fix the issue.

Published by the source

28 Apr 2025, 21:30 UTC

Last modified by the source

3 Nov 2025, 22:55 UTC

Source last checked

26 Oct 2026, 16:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3p2h-wqq4-wf4h

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# Patch Next advisory brief: CVE-2025-31650

Advisory: Apache Tomcat Denial of Service via invalid HTTP priority header
IDs: CVE-2025-31650, GHSA-3p2h-wqq4-wf4h
Record: https://patchnext.com/advisories/cve-2025-31650 (revision 1, source checked 26 Oct 2026, 16:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: org.apache.tomcat:tomcat-coyote 11.0.6, 10.1.40, 9.0.104; org.apache.tomcat.embed:tomcat-embed-core 11.0.6, 10.1.40, 9.0.104. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.tomcat:tomcat-coyote: affected >= 9.0.76, <= 9.0.102; >= 10.1.10, < 10.1.40; >= 11.0.0-M2, < 11.0.6; >= 8.5.0, <= 8.5.100; fixed in 9.0.104, 10.1.40, 11.0.6
- Maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 9.0.76, <= 9.0.102; >= 10.1.10, < 10.1.40; >= 11.0.0-M2, < 11.0.6; >= 8.5.0, <= 8.5.100; fixed in 9.0.104, 10.1.40, 11.0.6

## Suggested inspection (read-only)
- Maven org.apache.tomcat:tomcat-coyote: check the installed version with your package manager.
- Maven org.apache.tomcat.embed:tomcat-embed-core: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apache.tomcat:tomcat-coyote, org.apache.tomcat.embed:tomcat-embed-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3p2h-wqq4-wf4h (GitHub-reviewed advisory GHSA-3p2h-wqq4-wf4h lists affected ranges: Maven org.apache.tomcat:tomcat-coyote >=9.0.76 =10.1.10 =11.0.0-M2 =8.5.0 =9.0.76 =10.1.10 =11.0.0-M2 =8.5.0 <=8.5.100)

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