Executive brief
Hermes WebUI, a management interface for workspace repositories, is vulnerable to a security flaw that allows users to take control of the underlying server. By uploading or restoring a repository with a specially crafted configuration file, an attacker can force the system to run malicious commands during routine operations like checking repository status. This could lead to a total compromise of the application server and any data stored within it.
Technical details
A remote code execution (RCE) vulnerability exists in Hermes WebUI due to improper neutralization of Git configuration settings in workspace repositories. Authenticated attackers can inject malicious executable directives into a repository's .git/config file. When the application invokes Git subprocesses via api/workspace_git.py (such as during 'git status' or 'git fetch'), it may trigger these directives through vectors including core.fsmonitor, credential.helper, core.askPass, or protocol.ext.allow. The vulnerability also extends to inherited environment variables like GIT_SSH_COMMAND. This allows for arbitrary command execution on the host with the privileges of the application process. The issue is fixed in version 0.51.311 by enforcing hardened Git configuration overrides (-c) and scrubbing sensitive environment variables.
Affected products
- nesquena Hermes WebUI < 0.51.311
Timeline
- 2026-06-07: patched: Fix included in release v0.51.311
- 2026-06-09: disclosed: CVE published to NVD