_sanitize_proxy_path decoded the proxy path once before the '..' check, so a double-encoded payload (%252e%252e) survived the check as %2e%2e and was then re-decoded into '..' by the upstream terminal server, defeating the traversal guard. Decode until stable so no encoded traversal sequence can reach the upstream. Single-encoded payloads were already rejected; this closes the double (and deeper) encoding bypass.
Co-authored-by: sermikr0 <230672901+sermikr0@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
