AUGUST 25, 2026
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Case File

CVE-2026-12740

HIGH · CVSS 8.1 EPSS 0.17% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-07-04 · Last synced 2026-08-04

CyberRota Analysis

This is a high severity vulnerability with a CVSS score of 8.1. It affects Exchange. Public exploit code or proof-of-concept references have been detected in its references.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-12740
Severity
HIGH
CVSS
8.1
EPSS
0.17%
Exchange

Original NVD Description

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.