Vulnerability in Apache Software Foundation Apache CXF

[ Why it matters ]Priority signals

• Critical severity: CVSS 9.1

[ Description ]Official description

Apache CXF's STSTokenValidator and Security Token Service (STS) cached validated security tokens under a non-cryptographic 32-bit hash of the token (Java Arrays.hashCode/hashCode()), and treated a cache hit as proof that the presented token had already been validated. An attacker could craft a token (for example a UsernameToken or a self-signed SAML Assertion) whose hash collides with a cached entry. The token would then be accepted without password validation, signature trust verification or a call to the STS. This could let the attacker authenticate as another user and, through STS token validation or renewal, obtain STS-signed tokens for that identity. Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund8 Oct 2026WID-SEC-2026-3824

  Apache CXF: Multiple vulnerabilities Translated from German

  CVE-2026-78384CVE-2026-97791CVE-2026-108039+7 more CVEs

[ References ]References

• lists.apache.org/thread.html/qthbnsyhqsxhl9p2h9v5dg4mnwv1b9r6Issue TrackingVendor Advisory
• www.openwall.com/lists/oss-security/2026/10/09/9Mailing ListThird Party Advisory