CVE-2026-55885: Grav: Admin Backup Zip File Exposes Account Credentials and Configuration Secrets

An authenticated administrator with backup permissions can download a ZIP archive containing the full Grav installation root, including user/accounts/admin.yaml with the admin’s bcrypt password hash and email, plus user/config/ with all site configuration. The download endpoint requires only the session-static admin-nonce in the URL, no additional form-level CSRF token, and reveals the server’s full filesystem path in a Base64-encoded query parameter. Combined with the absence of login rate limiting on http://{Grav_URL}/admin, an attacker who obtains a single admin-nonce value (via Referrer leakage, browser history, or XSS) can exfiltrate password hashes for offline cracking and achieve account takeover.