CVE-2026-57817 Apache CXF: The authorization code hash (c_hash) is not enforced for the hybrid OIDC flow
Attackers can bypass authentication in Apache CXF hybrid OIDC flows if the Identity Provider omits the c_hash parameter, allowing authorization code injection.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-57817?
CVE-2026-57817 is a high-severity authentication bypass vulnerability in Apache Cxf, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The OpenID Connect Core 1.0 specification mandates that the RP MUST validate the `c_hash` parameter when operating in the Hybrid Flow. If an Apache CXF RP is integrated with a non-compliant or misconfigured Identity Provider (IdP) that omits the `c_hash`, the RP becomes vulnerable to Authorization Code Substitution/Injection attacks. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.
Weakness: CWE-20
Which versions are affected by CVE-2026-57817?
It affects 1 product.
Products include Apache Cxf.
How do I fix CVE-2026-57817?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-57817 being exploited?
There is no known exploitation of CVE-2026-57817 in the wild and no public exploit code.
Other vulnerabilities in Apache Cxf
- CVE-2012-2379 XML Signature/Encryption Not Validated in Apache CXF
- CVE-2026-66909 Apache CXF: Unsafe deserialization of inbound JMS ObjectMessage
- CVE-2026-68079 Apache CXF: DefaultEncryptingCodeDataProvider allows unlimited authorization code replay
- CVE-2026-50628 Apache CXF: OAuth2: Inverted IP Binding Check Defeats Security Control
- CVE-2025-48913 Apache CXF: Untrusted JMS configuration can lead to RCE
Sources
Also known as GHSA-h8f8-97w2-2925.