CVE-2026-86247: Apache Tomcat Native race condition in client certificate verification

CVE-2026-86247 · Severity: high · CVSS 7.4 · Published 2026-09-23

Apache Tomcat Native is a library that provides native bindings for Tomcat web servers, including SSL/TLS certificate handling. A race condition in certificate verification logic allows attackers to bypass client certificate requirements in certain configurations, potentially granting unauthorized access to applications that rely on certificate-based authentication.

Technologies: Apache Tomcat Native. Vendors: Apache.

Quick answers

Is CVE-2026-86247 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-86247 being exploited in the wild.
How severe is CVE-2026-86247?
High severity, with a CVSS score of 7.4, published 23 September 2026.
Which products and versions are affected?
Apache Tomcat Native 2.0.0 through 2.0.15, 1.3.0 through 1.3.8.
Is there a fix for CVE-2026-86247?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-86247 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-86247?
Check whether you run Apache Tomcat Native at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A race condition within a thread in Apache Tomcat Native allows client certificate verification requirements to be down-graded for some configurations. The vulnerability exists in versions 2.0.0-2.0.15 and 1.3.0-1.3.8. An attacker on the network can exploit this condition to bypass client certificate authentication protections; no user interaction or prior authentication is required.

Affected products

  • Apache Tomcat Native 2.0.0 through 2.0.15, 1.3.0 through 1.3.8

Timeline

  • 2026-09-23: disclosed

References

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