CVE-2026-49957 Hermes WebUI < 0.51.296 Workspace Boundary Bypass via api/workspace.py
Authenticated attackers can bypass workspace restrictions to read local system files by manipulating remote terminal working directory settings.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-49957?
CVE-2026-49957 is a medium-severity path traversal vulnerability in nesquena hermes-webui, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Hermes WebUI before version 0.51.296 contains a workspace boundary bypass vulnerability that allows authenticated attackers to circumvent blocked-root path checks by exploiting an early return in the SSH/remote terminal profile workspace resolution logic within _remote_terminal_workspace_candidate(). Attackers can configure a remote terminal working directory to a system directory such as /etc, causing the workspace resolution path to accept it as a trusted local workspace root before the _is_blocked_workspace_path() guard executes, enabling read access to local system files through workspace file-read helpers.
Weakness: CWE-22
Which versions are affected by CVE-2026-49957?
How do I fix CVE-2026-49957?
No fix has been published for CVE-2026-49957 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-49957 being exploited?
There is no known exploitation of CVE-2026-49957 in the wild and no public exploit code.
Sources
Also known as GHSA-5cwx-phm8-m83r.