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
Server-Side Request Forgery The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.