CVE-2026-54430

Server-Site Request Forgery in liboauth2

CVSS 5.1 MEDIUMEPSS 0.1%CWE-918

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 5.1EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

02 Jul 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:N/SA:N

Affected products

OpenIDC · liboauth2

References

https://cert.pl/en/posts/2026/07/CVE-2026-54430 https://github.com/OpenIDC/liboauth2 https://github.com/OpenIDC/liboauth2/commit/347507ac5b51f48c2933bbe49b2ee07c2af4712b