Vulnerability · Published Aug 6, 2026 · Assigned by apache
CVE-2026-63687Apache CXF: JwtRequestCodeFilter silently overrides outer PKCE and nonce parameters
Critical 9.1
In plain English
A critical-severity insufficient verification of data authenticity 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 0.3% (higher than 21% of all known vulnerabilities).
Official description
Apache CXF's JwtRequestCodeFilter copies all claims from a signed request JWT into the authorization parameter map without excluding security-sensitive parameters. A client that can produce a validly-signed request JWT (e.g., one whose client_secret is known or compromised) can thereby substitute the code_challenge, code_challenge_method, nonce, and state values that were set in the outer HTTP request, undermining PKCE integrity and OpenID Connect replay protection. 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-345 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N