GHSA-fpj8-gq4v-p354 is a critical-severity (CVSS 9.1) Improper Input Validation vulnerability in org.apache.tomcat.embed:tomcat-embed-core. A fix is available for org.apache.tomcat.embed:tomcat-embed-core — see the affected versions and patch details below.
Apache Tomcat - Client certificate verification bypass
Exploitation Status
No confirmed exploitation observed yet
- 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-fpj8-gq4v-p354.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-fpj8-gq4v-p354 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyote+4 moreReal-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
Improper Input Validation vulnerability.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.14, from 10.1.0-M1 through 10.1.49, from 9.0.0-M1 through 9.0.112.
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. Older EOL versions are not affected. Tomcat did not validate that the host name provided via the SNI extension was the same as the host name provided in the HTTP host header field. If Tomcat was configured with more than one virtual host and the TLS configuration for one of those hosts did not require client certificate authentication but another one did, it was possible for a client to bypass the client certificate authentication by sending different host names in the SNI extension and the HTTP host header field.
The vulnerability only applies if client certificate authentication is only enforced at the Connector. It does not apply if client certificate authentication is enforced at the web application.
Users are recommended to upgrade to version 11.0.15 or later, 10.1.50 or later or 9.0.113 or later, which fix the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.tomcat.embed:tomcat-embed-core | ≥ 11.0.0-M1&&< 11.0.15 | 11.0.15org.apache.tomcat.embed:tomcat-embed-core:11.0.15 |
| ☕Maven | org.apache.tomcat.embed:tomcat-embed-core | ≥ 10.1.0-M1&&< 10.1.50 | 10.1.50org.apache.tomcat.embed:tomcat-embed-core:10.1.50 |
| ☕Maven | org.apache.tomcat.embed:tomcat-embed-core | ≥ 9.0.0-M1&&< 9.0.113 | 9.0.113org.apache.tomcat.embed:tomcat-embed-core:9.0.113 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 11.0.0-M1&&< 11.0.15 | 11.0.15org.apache.tomcat:tomcat:11.0.15 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 10.1.0-M1&&< 10.1.50 | 10.1.50org.apache.tomcat:tomcat:10.1.50 |
| ☕Maven | org.apache.tomcat:tomcat | ≥ 9.0.0-M1&&< 9.0.113 | 9.0.113org.apache.tomcat:tomcat:9.0.113 |
Detection & mitigation playbook
Open-source dependencyDetect
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.
Fix
Update org.apache.tomcat.embed:tomcat-embed-core to 11.0.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fpj8-gq4v-p354 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-fpj8-gq4v-p354 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-fpj8-gq4v-p354. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | tomcat9-1:9.0.117-2.el10_2 | RHSA-2026:36790 |
| Red Hat JBoss Web Server 6.2.2 | tomcat | RHSA-2026:12195 |
| Red Hat JBoss Web Server 6.2 on RHEL 10 | jws6-tomcat-0:10.1.49-10.redhat_00008.1.el10jws | RHSA-2026:12194 |
| Red Hat Hardened Images | tomcat11-main-11.0.21-0.1.hum1 | RHSA-2026:6569 |
| Red Hat Hardened Images | tomcat10-main-10.1.54-1.hum1 | RHSA-2026:8334 |
Frequently Asked Questions
Is GHSA-fpj8-gq4v-p354 in your dependencies?
O3 Security finds GHSA-fpj8-gq4v-p354 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.