CVE-2026-49958 Details

A time-of-check time-of-use (TOCTOU) race condition vulnerability has been identified in Hermes WebUI versions prior to 0.51.303. The issue resides in the git_discard function within api/workspace_git.py. This vulnerability allows attackers to delete files outside the designated workspace boundary by replacing a validated path component with a symlink, after the validation process but before the deletion occurs. Exploitation involves substituting a workspace-controlled path component with a symlink pointing to an external directory, taking advantage of the window between the safe_resolve_ws() validation and the subsequent file deletion call. As a result, the deletion operation follows the symlink, leading to the removal of arbitrary files outside the workspace.

Users can update to Hermes WebUI version 0.51.303 or later, where this vulnerability has been addressed.