Vulnerability · Published Aug 6, 2026 · Assigned by apache
CVE-2026-57817Apache CXF: The authorization code hash (c_hash) is not enforced for the hybrid OIDC flow
High 8.1
In plain English
A high-severity improper input validation in Apache CXF from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities).
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache CXF | 4.2.0 – before 4.2.34.0.0 – before 4.1.80 – before 3.6.12 |
Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H