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HIGH severity

Apache Tomcat is vulnerable to resource exhaustion when using the APR/Native connectorGHSA-4j3c-42xv-3f84

HIGHFix: apache/tomcat@8a83c3c

GHSA-4j3c-42xv-3f84 is a high-severity (CVSS 7.5) CWE-362 vulnerability in org.apache.tomcat:tomcat-coyote. A fix is available for org.apache.tomcat:tomcat-coyote — see the affected versions and patch details below.

Also known asBIT-tomcat-2025-52434CVE-2025-52434
Published
Updated
Affected
4 pkgs
Patched
2 / 4
Exploits
None indexed
Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-4j3c-42xv-3f84.

EPSS Exploitation Probability

via FIRST.org ↗
2.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs82th percentile — riskier than 82% of all scored CVEsHighest risk
0.05%0.89%1.73%2.57%0.6%2.1%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

4 pkgs affected
☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat.embed:tomcat-embed-core☕org.apache.tomcat.embed:tomcat-embed-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

4 total 2 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.apache.tomcat:tomcat-coyote≥ 9.0.0.M1&&< 9.0.1079.0.107org.apache.tomcat:tomcat-coyote:9.0.107
☕Mavenorg.apache.tomcat:tomcat-coyote≥ 8.5.0No fix
☕Mavenorg.apache.tomcat.embed:tomcat-embed-core≥ 9.0.0.M1&&< 9.0.1079.0.107org.apache.tomcat.embed:tomcat-embed-core:9.0.107
☕Mavenorg.apache.tomcat.embed:tomcat-embed-core≥ 8.5.0No fix

Affected Products

1 product · 1 configurations
Application
tomcatapache
≥ 9.0.0 && < 9.0.107
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat-coyote, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.apache.tomcat:tomcat-coyote to 9.0.107 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4j3c-42xv-3f84 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate
ProductFixed inAdvisory
Red Hat Enterprise Linux 10tomcat9-1:9.0.87-5.el10_0.3RHSA-2025:14178
Red Hat Enterprise Linux 8tomcat-1:9.0.87-1.el8_10.6RHSA-2025:14177
Red Hat Enterprise Linux 8.8 Telecommunications Update Servicetomcat-1:9.0.87-1.el8_8.7RHSA-2025:14182
Red Hat Enterprise Linux 9tomcat-1:9.0.87-3.el9_6.3RHSA-2025:14181
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutionstomcat-1:9.0.87-1.el9_2.6RHSA-2025:14183
Red Hat Enterprise Linux 9.4 Extended Update Supporttomcat-1:9.0.87-1.el9_4.6RHSA-2025:14180
Red Hat JBoss Web Server 5.8.5jws5-tomcatRHSA-2025:11696
Red Hat JBoss Web Server 5.8 on RHEL 7jws5-tomcat-0:9.0.87-12.redhat_00011.1.el7jwsRHSA-2025:11695

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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