CVE-2026-54430: Openidc LIBOAUTH2

Medium severity, CVSS 5.1. EPSS: 0.2% chance of exploitation in the next 30 days.

liboauth2 is vulnerable to Server-Side Request Forgery in oauth2_jose_jwks_aws_alb_resolve() function. The AWS ALB verifier reads both signer and kid from the unverified JWT header. If signer matches the configured ARN, kid is appended to alb_base_url without URL encoding or path sanitization, and the HTTP GET is issued before signature verification. This allows an attacker to force the server to send a GET request to an attacker-chosen internal path. This issue was fixed in version 2.3.0

Affected products

• Openidc LIBOAUTH2: before 2.3.0 (fixed in 2.3.0)

Published 2026-07-02. Last modified 2026-07-02.