---
id: CVE-2026-63478
title: >-
  isomorphic-git: Path traversal via a ".." tree-entry name writes files outside
  the working directory on clone/checkout
summary: >-
  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. D…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-22
vendor: isomorphic-git
product: isomorphic-git
affected:
  - isomorphic-git < 1.38.6
published: '2026-11-03'
updated: '2026-11-03'
sourceUpdated: '2026-11-03T19:39:52.188Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63478'
references:
  - url: >-
      https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-cw2g-2vwq-88w6
    label: >-
      https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-cw2g-2vwq-88w6
  - url: 'https://github.com/isomorphic-git/isomorphic-git/pull/2370'
    label: 'https://github.com/isomorphic-git/isomorphic-git/pull/2370'
  - url: >-
      https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b
    label: >-
      https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b
  - url: 'https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6'
    label: 'https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6'
tags:
  - cve.org
epss: 0.00295
epssPercentile: 0.22335
ingestedAt: '2026-11-05T20:33:06.401Z'
---

## Overview

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.

## Affected

- `isomorphic-git < 1.38.6`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.