CVE-2026-34454

Impact

A regression introduced in v7.11.0 is preventing OAuth2 Proxy from clearing the session cookie when rendering the sign-in page.

This only impacts deployments that rely on the sign-in page as part of their logout flow. In those setups, a user may be shown the sign-in page while the existing session cookie remains valid, so the browser session is not actually logged out. On shared workstations be it browsers or devices, a subsequent user could continue to use the previous user's authenticated session.

Deployments that use a dedicated logout/sign-out endpoint to terminate sessions are not affected.

Patches

This issue is fixed in v7.15.2.

Workarounds

Do not rely on the sign-in page to clear an existing session. Instead:

• Use the dedicated logout/sign-out endpoint of OAuth2 Proxy
• Ensure your application logout flow explicitly clears the OAuth2 Proxy session cookie before redirecting users to the sign-in page
• If needed, clear the session cookie at the reverse proxy or application layer as a temporary mitigation