How severe is CVE-2026-27735?

No CVSS score has been assigned to CVE-2026-27735 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-27735?

CVE-2026-27735 affects the following packages: mcp-server-git (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-27735?

Update mcp-server-git to 2026.1.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27735 is resolved across your whole dependency graph.

How do I detect CVE-2026-27735 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mcp-server-git, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-27735 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-27735?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-27735 can be triaged on real exposure rather than presence alone.

Is CVE-2026-27735 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-27735 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-27735?

CVE-2026-27735 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 21th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-27735?

CVE-2026-27735 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-27735 published, and has it been updated?

CVE-2026-27735 was published on February 25, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-27735 — mcp-server-git

Fix: modelcontextprotocol/servers#3164

CVE-2026-27735 is a Path Traversal vulnerability in mcp-server-git. A fix is available for mcp-server-git — see the affected versions and patch details below.

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

Also known asGHSA-vjqx-cfc4-9h6vPYSEC-2026-2630

Published

Feb 25, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-27735.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs21th percentile — riskier than 21% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

🐍mcp-server-git

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

In mcp-server-git versions prior to 2026.1.14, the git_add 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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`mcp-server-git`	all versions	2026.1.14`pip install --upgrade 'mcp-server-git==2026.1.14'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mcp-server-git, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mcp-server-git to 2026.1.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27735 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-27735 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-27735. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In `mcp-server-git` versions prior to 2026.1.14, the `git_add` 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 C

O3 Security · Impact-Aware SCA

Is CVE-2026-27735 in your dependencies?

O3 Security finds CVE-2026-27735 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works