CVE-2026-63687

Critical

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.

SeverityCritical
CVSS9.1
Exploit probability—
ProductApache Cxf
PublishedAug 6, 2026
First seenAug 6, 2026
Weakness typeCWE-345CWE-345

How to fix

Update
  • apache cxf3.6.12, 4.1.8, 4.2.3 or later

Affected products

ProductAffected versionsFixed in
apache cxfv < 3.6.12, 4.0.0 ≤ v < 4.1.8, 4.2.0 ≤ v < 4.2.33.6.12, 4.1.8, 4.2.3

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