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
apache: cxf
References2
- lists.apache.org/thread/pj63c3pf7kkp1xhr53do704fwj3t3htn Mailing ListVendor Advisory
- www.openwall.com/lists/oss-security/2026/08/06/19
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 53 · as of 12 November 2026
- CWE
- CWE-20
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