PT-2026-54957 · Openid · Liboauth2

Marcin Wyczechowski + 1 · Published 2026-07-02 · Updated 2026-07-02 · CVE-2026-54430

NVD

CVSS v4.0

5.1

Medium

Base vector

AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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

Fix

SSRF

Weakness Enumeration

CWE-918

Related Identifiers

CVE-2026-54430

Affected Products

Liboauth2

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2026-54430 · Security Note
• https://github.com/OpenIDC/liboauth2/commit/347507ac5b51f48c2933bbe49b2ee07c2af4712b · Note
• https://github.com/OpenIDC/liboauth2 · Note
• https://cert.pl/en/posts/2026/07/CVE-2026-54430 · Note
• https://cert.pl/en/posts/2026/06/CVE-2026-54430 · Note