CVE-2026-54430

Summary

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 Software

Weaknesses

• CWE-918: CWE-918 Server-Side Request Forgery (SSRF)

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

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

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