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Exposure of Sensitive Information to an Unauthorized Actor in Apache TomcatGHSA-j39c-c8hj-x4j3

HIGH

GHSA-j39c-c8hj-x4j3 is a high-severity (CVSS 7.5) Information Exposure vulnerability in org.apache.tomcat.embed:tomcat-embed-core. EPSS puts its 30-day exploitation probability at 18.1% (97th percentile). A fix is available for org.apache.tomcat.embed:tomcat-embed-core — see the affected versions and patch details below.

Also known asBIT-tomcat-2021-25122CVE-2021-25122
Published
Updated
Affected
4 pkgs
Patched
4 / 4
Exploits
None indexed
Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
18.1%probability of exploitation in next 30 days
Moderate Risk0.00%
Lower risk than most CVEs97th percentile — riskier than 97% of all scored CVEsHighest risk

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

How urgent is this, really

GHSA-j39c-c8hj-x4j3 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

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

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

When responding to new h2c connection requests, Apache Tomcat versions 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41 and 8.5.0 to 8.5.61 could duplicate request headers and a limited amount of request body from one request to another meaning user A and user B could both see the results of user A's request.

Affected Packages

4 total 4 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.apache.tomcat.embed:tomcat-embed-core≥ 10.0.0-M1&&< 10.0.210.0.2org.apache.tomcat.embed:tomcat-embed-core:10.0.2
☕Mavenorg.apache.tomcat.embed:tomcat-embed-core≥ 9.0.0-M1&&< 9.0.439.0.43org.apache.tomcat.embed:tomcat-embed-core:9.0.43
☕Mavenorg.apache.tomcat.embed:tomcat-embed-core≥ 8.5.0&&< 8.5.638.5.63org.apache.tomcat.embed:tomcat-embed-core:8.5.63
☕Mavenorg.apache.tomcat:tomcat-coyote≥ 10.0.0-M1&&< 10.0.210.0.2org.apache.tomcat:tomcat-coyote:10.0.2

Affected Products

12 products · 55 configurations
Application
tomcatapache
≥ 9.0.0 && ≤ 9.0.41
2 versions
9.0.010.0.0
OS
debian linuxdebian
2 versions
9.010.0
Application
agile product lifecycle managementoracle
2 versions
9.3.39.3.6
Application
communications cloud native core policyoracle
1 version
1.14.0
Application
communications cloud native core security edge protection proxyoracle
1 version
1.6.0
Application
communications instant messaging serveroracle
1 version
10.0.1.5.0

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.embed:tomcat-embed-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.apache.tomcat.embed:tomcat-embed-core to 10.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-j39c-c8hj-x4j3 is resolved across your whole dependency graph.

  3. Workarounds

    Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

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

Red Hat Enterprise Linux 8's Identity Management and Certificate System are using a vulnerable version of Tomcat that is bundled into the `pki-servlet-engine` component. However, HTTP/2 is not enabled in such a configuration, and it is not possible to trigger the flaw in a supported setup. A future update may fix the…

ProductFixed inAdvisory
Red Hat Fuse 7.11tomcatRHSA-2022:5532
Red Hat JBoss Web Server 5tomcatRHSA-2021:2562
Red Hat JBoss Web Server 5.5 on RHEL 7jws5-ecj-0:4.12.0-3.redhat_2.2.el7jwsRHSA-2021:2561
Red Hat support for Spring Boot 2.3.10tomcatRHSA-2021:3425

Frequently Asked Questions

When responding to new h2c connection requests, Apache Tomcat versions 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41 and 8.5.0 to 8.5.61 could duplicate request headers and a limited amount of request body from one request to another meaning user A and user B could both see the results of user A's request.
O3 Security · Impact-Aware SCA

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Exposure of Sensitive Information to an Unauthorized…