{"cve":"CVE-2026-12740","nvd":{"published":"2026-07-04T18:16:28.133","modified":"2026-10-25T15:10:00.147","status":"Deferred","description":"Plack::Middleware::OAuth versions through 0.10 for Perl do not support the OAuth 2.0 state parameter.\n\nRequestTokenV2 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.\n\nAny 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N","score":8.1},"cwes":["CWE-352"],"references":["https://datatracker.ietf.org/doc/html/rfc6749#section-10.12","https://github.com/c9s/Plack-Middleware-OAuth/pull/13","https://rt.cpan.org/Ticket/Display.html?id=179874","https://security.metacpan.org/patches/P/Plack-Middleware-OAuth/0.10/CVE-2026-12740-r1.patch","http://www.openwall.com/lists/oss-security/2026/07/04/10"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:06.907763985+00:00"},"epss":{"cve":"CVE-2026-12740","score":0.00234,"percentile":0.14195,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}