Vulnerability · Published Jun 9, 2026 · Assigned by VulnCheck

CVE-2026-49958Hermes WebUI < 0.51.303 TOCTOU Race Condition via git_discard

Medium 5.0

In plain English

A medium-severity security flaw in hermes-webui from nesquena. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 0% of all known vulnerabilities).

Severity (CVSS 3.1)5.0Medium

Exploit odds (30 days)<0.1%top 99.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Hermes WebUI before version 0.51.303 contains a time-of-check time-of-use (TOCTOU) race condition vulnerability in the git_discard function within api/workspace_git.py that allows attackers to delete files outside the configured workspace boundary by replacing a validated path component with a symlink after validation but before deletion. Attackers can substitute a workspace-controlled path component with a symlink pointing to an external directory between the safe_resolve_ws() validation step and the subsequent Path.unlink() or shutil.rmtree() deletion call, causing the delete operation to follow the symlink and remove arbitrary files outside the workspace.

Affected products (as reported)

Vendor	Product	Versions
nesquena	hermes-webui	0 – before 0.51.303

Weakness: CWE-367 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:H

References

https://github.com/nesquena/hermes-webui/releases/tag/v0.51.303 release-notes
https://github.com/nesquena/hermes-webui/pull/3702 issue-tracking
https://github.com/nesquena/hermes-webui/pull/3756 issue-tracking
https://github.com/nesquena/hermes-webui/commit/4580f584964d640b95c4ffc9245a21ab926bec73 patch
https://www.vulncheck.com/advisories/hermes-webui-toctou-race-condition-via-git-discard third-party-advisory