CVE-2026-12740
HighCVSS 8.1Exploitation Probability (EPSS)
Low risk3th percentile — higher than 3% of all known CVEs
Summary
The vulnerability in Plack::Middleware::OAuth for Perl up to version 0.10 does not support the OAuth 2.0 state parameter. The lack of callback-to-session binding allows login cross-site request forgery, where an attacker can inject their own access token into the victim's session.
Risk Assessment
The organization risks account takeover, as an attacker can associate their provider identity with the victim's session, potentially gaining persistent unauthorized access to the victim's account.
Recommendation
Immediately update Plack::Middleware::OAuth to a version that implements the OAuth 2.0 state parameter, or deploy an alternative solution that enforces session binding for authorization callbacks.
Original NVD description (English source)
Plack::Middleware::OAuth versions through 0.10 for Perl do not support the OAuth 2.0 state parameter. RequestTokenV2 builds the provider authorization redirect without issuing a state value, and AccessTokenV2 exchanges the callback code and registers the resulting token into the session (register_session) without verifying that the callback corresponds to an authorization request this session initiated. Any application that uses this middleware for OAuth 2.0 login is exposed to login cross-site request forgery: because the callback is not bound to the session that began the flow, an attacker who starts an authorization with their own provider account can deliver the resulting callback to a victim, causing the victim's session to complete the attacker's authorization and associating the attacker's provider identity and access token with that session. Where the application persists this as an account link, the attacker may retain access to the victim's account through their own provider credentials.