CVE-2026-97468: Apache CXF: Authentication bypass via weak cache keys for validated STS tokens
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Apache CXFto a version that resolves this vulnerability.Fixed in 4.2.4 - Upgrade
Upgrade
Apache CXFto a version that resolves this vulnerability.Fixed in 4.1.9 - Upgrade
Upgrade
Apache CXFto a version that resolves this vulnerability.Fixed in 3.6.13
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments using Apache CXF's STSTokenValidator or Security Token Service token-validation caching are exposed when a validated token can be present in the cache. The issue affects validation of tokens such as UsernameTokens and self-signed SAML assertions.
What does an attacker need to exploit the bypass?
The attacker needs to craft and present a token whose non-cryptographic 32-bit hash collides with a token already cached as validated. A successful collision can cause the crafted token to be accepted without password validation, signature trust verification, or an STS call.
What is the impact after a successful cache collision?
An attacker may authenticate as another user associated with the cached token. They may also use STS token validation or renewal to obtain STS-signed tokens for that identity.
What versions contain the fix?
Upgrade Apache CXF to version 4.2.4, 4.1.9, or 3.6.13.