Vulnerability Advisory : OpenClaw < 2026.4.2 - PKCE Verifier Exposure via OAuth State Parameter with HIGH Attack Complexity

OpenClaw before 2026.4.2 reuses the PKCE verifier as the OAuth state parameter in the Gemini OAuth flow, exposing it through the redirect URL. Attackers who capture the redirect URL can obtain both the authorization code and PKCE verifier, defeating PKCE protection and enabling token redemption.