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
References (3)
Core 3
Core References
Third Party Advisory third-party-advisory
https://cert.pl/en/posts/2026/07/CVE-2026-54430
Product product
https://github.com/OpenIDC/liboauth2
Issue Tracking issue-tracking
https://github.com/OpenIDC/liboauth2/commit/347507ac5b51f48c2933bbe49b2ee07c2af4712b
Scores
CVSS v4
5.1
EPSS
0.0012
EPSS Percentile
2.3%
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/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
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-918
Status
published
Products (1)
OpenIDC/liboauth2
< 2.3.0
Published
Jul 02, 2026
Tracked Since
Jul 02, 2026