Apache Tomcat is vulnerable to resource exhaustion when using the APR/Native connector

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2025-52434: 2.07% estimated exploitation activity in the next 30 days; percentile 81.49 (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.

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in Apache Tomcat when using the APR/Native connector. This was particularly noticeable with client initiated closes of HTTP/2 connections. This issue affects Apache Tomcat: from 9.0.0.M1 through 9.0.106. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 through 8.5.100. Other, older, EOL versions may also be affected. Users are recommended to upgrade to version 9.0.107, which fixes the issue.

Published by the source

10 Jul 2025, 21:31 UTC

Last modified by the source

1 Jul 2026, 16:16 UTC

Source last checked

26 Oct 2026, 16:54 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4j3c-42xv-3f84

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# Patch Next advisory brief: CVE-2025-52434

Advisory: Apache Tomcat is vulnerable to resource exhaustion when using the APR/Native connector
IDs: CVE-2025-52434, GHSA-4j3c-42xv-3f84
Record: https://patchnext.com/advisories/cve-2025-52434 (revision 1, source checked 26 Oct 2026, 16:54 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
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 9.0.107; org.apache.tomcat.embed:tomcat-embed-core 9.0.107. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.tomcat:tomcat-coyote: affected >= 9.0.0.M1, < 9.0.107; >= 8.5.0, <= 8.5.100; fixed in 9.0.107
- Maven org.apache.tomcat.embed:tomcat-embed-core: affected >= 9.0.0.M1, < 9.0.107; >= 8.5.0, <= 8.5.100; fixed in 9.0.107

## 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-4j3c-42xv-3f84 (GitHub-reviewed advisory GHSA-4j3c-42xv-3f84 lists affected ranges: Maven org.apache.tomcat:tomcat-coyote >=9.0.0.M1 =8.5.0 =9.0.0.M1 =8.5.0 <=8.5.100)

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