mcp-server-git : Path traversal in git_add allows staging files outside repository boundaries

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N · score source

EPSS

• CVE-2026-27735: 0.34% estimated exploitation activity in the next 30 days; percentile 28.08 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

In mcp-server-git versions prior to 2026.1.14, the gitadd tool did not validate that file paths provided in the files argument were within the repository boundaries. The tool used GitPython's repo.index.add(, which did not enforce working-tree boundary checks for relative paths. As a result, relative paths containing ../ sequences that resolved outside the repository were accepted and staged into the Git index, potentially allowing sensitive files to be exfiltrated via subsequent commit and push operations. The fix in PR #3164 switches to repo.git.add(), which delegates to the Git CLI and properly rejects out-of-tree paths. Users are advised to upgrade to 2026.1.14 or newer to remediate this issue. mcp-server-git thanks https://hackerone.com/0dd-g for reporting and contributing the fix.

Published by the source

26 Feb 2026, 15:16 UTC

Last modified by the source

13 Jul 2026, 16:42 UTC

Source last checked

26 Oct 2026, 13:36 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-vjqx-cfc4-9h6v

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-vjqx-cfc4-9h6v

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# Patch Next advisory brief: CVE-2026-27735

Advisory: mcp-server-git : Path traversal in git_add allows staging files outside repository boundaries
IDs: CVE-2026-27735, GHSA-vjqx-cfc4-9h6v
Record: https://patchnext.com/advisories/cve-2026-27735 (revision 3, source checked 26 Oct 2026, 13:36 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mcp-server-git 2026.1.14. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI mcp-server-git: affected < 2026.1.14; fixed in 2026.1.14

## Suggested inspection (read-only)
- `python -m pip show mcp-server-git`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mcp-server-git.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-vjqx-cfc4-9h6v (OSV record GHSA-vjqx-cfc4-9h6v lists affected ranges: PyPI mcp-server-git >=0 <2026.1.14 (fixed))
- Verified: https://github.com/advisories/GHSA-vjqx-cfc4-9h6v (GitHub-reviewed advisory GHSA-vjqx-cfc4-9h6v lists affected ranges: PyPI mcp-server-git >=0 <2026.1.14)

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