CVE-2026-54430
MediumCVSS 5.1Summary
The liboauth2 library is vulnerable to Server-Side Request Forgery (SSRF) in the 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, the kid value is appended to alb_base_url without URL encoding or path sanitization, and the HTTP GET request is issued before signature verification.
Risk Assessment
An attacker can force the server to send a GET request to an attacker-chosen internal path, potentially leading to disclosure of sensitive data, privilege escalation, or further attacks on internal infrastructure.
Recommendation
Immediately update the liboauth2 library to version 2.3.0 or later, which contains the fix for this vulnerability.
Original NVD description (English source)
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