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PatchSiren cyber security CVE debrief

CVE-2026-49959 nesquena CVE debrief

CVE-2026-49959 is a high-severity remote code execution vulnerability in Hermes WebUI versions before 0.51.311. Authenticated attackers can exploit this via Git configuration injection to execute arbitrary commands on the host running the application. The vulnerability is caused by the application's use of Git subprocess invocations in api/workspace_git.py, which can be exploited through various 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.

Vendor
nesquena
Product
hermes-webui
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-07-14
Advisory published
2026-06-09
Advisory updated
2026-07-14

Who should care

Users of Hermes WebUI versions before 0.51.311 should apply the patch to prevent exploitation of this vulnerability.

Technical summary

The vulnerability has a CVSS score of 8.7 and is classified as HIGH severity. It can be exploited by authenticated attackers with low privileges.

Defensive priority

HIGH

Recommended defensive actions

  • Upgrade to Hermes WebUI version 0.51.311 or later.
  • Review and restrict access to Git configuration files in workspace repositories.
  • Monitor for suspicious activity in Git subprocess invocations.

Evidence notes

Evidence for this CVE comes from Vulncheck and the National Vulnerability Database (NVD).

Sources and references

Verified primary and authoritative sources

  • CVE-2026-49959 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-49959

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-49959 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-49959

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.