CVE-2026-54430

Server-Site Request Forgery in liboauth2

State: Published
Severity: 5.1 Medium
Published: Jul 2, 2026
Updated: Jul 2, 2026
Reserved: Jun 15, 2026

Description

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

Scores

CVSS	Score	Vector	Source
4.0	5.1 Medium	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	CERT-PL

Weaknesses

CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

Product	Versions
liboauth2OpenIDC	before 2.3.0Affected

References

https://cert.pl/en/posts/2026/07/CVE-2026-54430third-party-advisory
https://github.com/OpenIDC/liboauth2product
https://github.com/OpenIDC/liboauth2/commit/347507ac5b51f48c2933bbe49b2ee07c2af4712bissue-tracking

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