Hermes WebUI CVE-2026-49957

Hermes WebUI (nesquena/hermes-webui) is a web-based interface that includes an SSH/remote terminal integration allowing users to configure remote terminal profiles with custom working directories. Workspace resolution for these profiles is handled by _remote_terminal_workspace_candidate() in api/workspace.py. Under the vulnerable logic, candidate resolution for the remote cwd path executed an early return before invoking _is_blocked_workspace_path(), which is responsible for rejecting system directory roots such as /etc. Because the path was accepted as a trusted local workspace root prematurely, downstream file-read helpers - designed for safe workspace file access - would faithfully read from the resolved system path on the server. The root cause class is CWE-22 (Improper Limitation of a Pathname to a Restricted Directory / Path Traversal): user-controlled input (the SSH profile cwd) influences server-side path resolution without adequate pre-acceptance validation. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N) indicates this is network-accessible with low complexity, requiring no special attack prerequisites beyond a low-privileged account. The fix (commit 91a89fb5d5c0bf87932917f9914ad0150ea62fe4, PR #3731) adds if _is_blocked_workspace_path(candidate, raw) or _is_blocked_workspace_path(base, cwd): return None immediately within _remote_terminal_workspace_candidate(), ensuring the guard runs for both the derived candidate and the raw base path before any early return.