CVE-2026-49959: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in nesquena hermes-webui
Hermes WebUI before version 0.51.311 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary commands by placing malicious executable Git configuration in a workspace repository's .git/config file. Attackers can exploit Git subprocess invocations in api/workspace_git.py through vectors such as core.fsmonitor during git status, protocol.ext.allow with ext:: remotes during git fetch, credential.helper, core.askPass, core.gitProxy, or inherited environment variables including GIT_SSH_COMMAND to achieve arbitrary command execution on the host running the application.
AI Analysis
Technical Summary
CVE-2026-49959 is a remote code execution vulnerability in nesquena's Hermes WebUI before version 0.51.311. Authenticated attackers can exploit improper neutralization of special elements in Git configuration files (.git/config) within workspace repositories. The vulnerability arises from unsafe handling of Git subprocess invocations in api/workspace_git.py, including vectors like core.fsmonitor during git status, protocol.ext.allow with ext:: remotes during git fetch, credential.helper, core.askPass, core.gitProxy, and inherited environment variables such as GIT_SSH_COMMAND. This allows execution of arbitrary OS commands on the host running the application.
Potential Impact
Successful exploitation enables authenticated attackers to execute arbitrary commands on the host system, potentially leading to full system compromise, data theft, or disruption of services. The vulnerability requires authentication but has a high impact due to the ability to execute OS-level commands with the privileges of the application.
Mitigation Recommendations
No official patch or remediation guidance is currently confirmed. Users should upgrade Hermes WebUI to version 0.51.311 or later once available. Until then, restrict access to trusted users only and monitor for suspicious activity related to Git operations within the application. Check the vendor advisory regularly for updates on patches or official fixes.
CVE-2026-49959: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in nesquena hermes-webui
Description
Hermes WebUI before version 0.51.311 contains a remote code execution vulnerability that allows authenticated attackers to execute arbitrary commands by placing malicious executable Git configuration in a workspace repository's .git/config file. Attackers can exploit Git subprocess invocations in api/workspace_git.py through vectors such as core.fsmonitor during git status, protocol.ext.allow with ext:: remotes during git fetch, credential.helper, core.askPass, core.gitProxy, or inherited environment variables including GIT_SSH_COMMAND to achieve arbitrary command execution on the host running the application.
CVSS v4.0
Score 8.7high
Affected software
pkg:github/nesquena/hermes-webuiRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-49959 is a remote code execution vulnerability in nesquena's Hermes WebUI before version 0.51.311. Authenticated attackers can exploit improper neutralization of special elements in Git configuration files (.git/config) within workspace repositories. The vulnerability arises from unsafe handling of Git subprocess invocations in api/workspace_git.py, including vectors like core.fsmonitor during git status, protocol.ext.allow with ext:: remotes during git fetch, credential.helper, core.askPass, core.gitProxy, and inherited environment variables such as GIT_SSH_COMMAND. This allows execution of arbitrary OS commands on the host running the application.
Potential Impact
Successful exploitation enables authenticated attackers to execute arbitrary commands on the host system, potentially leading to full system compromise, data theft, or disruption of services. The vulnerability requires authentication but has a high impact due to the ability to execute OS-level commands with the privileges of the application.
Mitigation Recommendations
No official patch or remediation guidance is currently confirmed. Users should upgrade Hermes WebUI to version 0.51.311 or later once available. Until then, restrict access to trusted users only and monitor for suspicious activity related to Git operations within the application. Check the vendor advisory regularly for updates on patches or official fixes.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-06-02T16:30:15.233Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a284d1c8dd33fbd85665b5c
Added to database: 06/09/2026, 17:27:56 UTC
Last enriched: 07/15/2026, 10:08:54 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 91
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