Apache CXF STSTokenValidator Remote Unauth Token Acceptance (4.2.4)
CVE-2026-97791 Published on October 9, 2026
Apache CXF: STSTokenValidator can accept untrusted SAML assertions because it shares validation state between requests
In Apache CXF, STSTokenValidator checks whether a SAML assertion is signed by a trusted certificate before deciding to send it to the STS. That result was stored in one object shared by all requests, so one request could read another's result. A remote, unauthenticated attacker could send a forged assertion signed with an untrusted certificate while legitimate requests were being processed, and it could be accepted as trusted without ever reaching the STS. Only services that use STSTokenValidator to validate SAML tokens without alwaysValidateToSts set are affected.
Users are recommended to upgrade to versions 4.2.4 or 4.1.9 or 3.6.13, which fix this issue.
Vulnerability Analysis
CVE-2026-97791 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Race Condition Vulnerability?
The program contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.
CVE-2026-97791 has been classified to as a Race Condition vulnerability or weakness.
Products Associated with CVE-2026-97791
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Affected Versions
Apache Software Foundation Apache CXF:- Version 4.2.0 and below 4.2.4 is affected.
- Version 4.0.0 and below 4.1.9 is affected.
- Before 3.6.13 is affected.