CVE-2026-63478

isomorphic-git: Path traversal via a ".." tree-entry name writes files outside the working directory on clone/checkout

Published Nov 3, 2026 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git's tree parser in src/models/GitTree.js accepts a standalone .. tree-entry name because it rejects only path separators. During clone or checkout from a malicious or man-in-the-middle-controlled non-GitHub remote, nested .. entries can escape the working-tree root and write files at attacker-selected parent paths on any host-backed fs provider. The arbitrary file write can overwrite startup or configuration files and lead to code execution. GitHub-hosted trees are not a direct source because GitHub rejects .. entries during repository integrity checks. This issue is fixed in version 1.38.6.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-cw2g-2vwq-88w6 isomorphic-git: Path traversal via a ".." tree-entry name writes files outside the working directory on clone/checkout
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Isomorphic-git
Isomorphic-git isomorphic-git
Vendors & Products Isomorphic-git
Isomorphic-git isomorphic-git
Type Values Removed Values Added
Description isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git's tree parser in src/models/GitTree.js accepts a standalone .. tree-entry name because it rejects only path separators. During clone or checkout from a malicious or man-in-the-middle-controlled non-GitHub remote, nested .. entries can escape the working-tree root and write files at attacker-selected parent paths on any host-backed fs provider. The arbitrary file write can overwrite startup or configuration files and lead to code execution. GitHub-hosted trees are not a direct source because GitHub rejects .. entries during repository integrity checks. This issue is fixed in version 1.38.6.
Title isomorphic-git: Path traversal via a ".." tree-entry name writes files outside the working directory on clone/checkout
Weaknesses CWE-22
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Nov 7, 2026, 3:26 AM
Reserved
Jul 16, 2026, 9:37 PM
Status
Deferred
Published
Nov 3, 2026, 8:18 PM
Modified
Nov 7, 2026, 4:17 AM
Severity
Moderate
Public date
Nov 3, 2026, 7:39 PM