Medium File handling

CVE-2026-27735 — mcp-server-git : Path traversal in git_add allows staging files outside repository boundaries

Model Context Protocol Servers is a collection of reference implementations for the model context protocol (MCP). 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. Because the tool used GitPython's repo.index.add() rather than the Git CLI, relative paths containing `../` sequences that resolve outside the repository were accepted and staged into the Git index. Users are advised to upgrade to 2026.1.14 or newer to remediate this issue.

Published Feb 25, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.5% (30-day exploitation probability)+6
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.47%

ahead of 39% of scored CVEs · Oct 14, 2026

Affects

Lfprojects

Model Context Protocol Servers and 1 more

CVSS base

6.5

Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — github.com (NIST National Vulnerability Database)
Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Lfprojects Model Context Protocol Servers, Modelcontextprotocol Servers).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Lfprojects	Model Context Protocol Servers	< 2026.1.14	Vulnerable	NIST National Vulnerability Database
Modelcontextprotocol	Servers	version < 2026.1.14	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
6.4	CVSS 4.0	Medium	—	—	security-advisories@github.com via NIST National Vulnerability Database
6.4	CVSS 4.0	Medium	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP
6.5	CVSS 3.1	Medium	2.8	3.6	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-22 · Path Traversal

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.47%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Monitor file creation in web directories and paths with traversal sequences (../).

web/proxy/WAF logsnetwork IDS/IPSfile integrity (FIM)endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · modelcontextprotocol/servers
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 6.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Feb 25, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

github.com/modelcontextprotocol/servers/pull/3164
Issue Tracking, Patch, x_refsource_MISC, NIST National Vulnerability Database
github.com/modelcontextprotocol/servers/security/advisories/GHSA-vjqx-cfc4-9h6v
Patch, Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database

Elsewhere on this site

Lfprojects
every CVE for this vendor

File handling
same class

CWE-22
other pages naming this weakness

Related CVEs (same products)

High CVE-2025-68143 mcp-server-git's unrestricted git_init tool allows repository creation at arbitrary filesystem locations Dec 17, 2025
High CVE-2025-68144 mcp-server-git argument injection in git_diff and git_checkout functions allows overwriting local files Dec 17, 2025
Critical CVE-2025-68145 mcp-server-git has missing path validation when using --repository flag Dec 17, 2025

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-27735 is "mcp-server-git : Path traversal in git_add allows staging files outside repository boundaries", rated Medium. It affects Model Context Protocol Servers (Lfprojects); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.47% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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