---
id: CVE-2026-63475
title: >-
  isomorphic-git: Circular symbolic references cause non-terminating resolution
  (DoS)
summary: >-
  isomorphic-git is a pure JavaScript implementation of Git for Node.js and
  browsers. Prior to 1.38.6, isomorphic-git persists server-supplied circular
  symref= capabilities through updateRemoteRefs, and GitRefManager.resolve()
  follows the …
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-674
  - CWE-835
vendor: isomorphic-git
product: isomorphic-git
affected:
  - isomorphic-git < 1.38.6
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-03T21:30:35.793171Z'
exploitAvailable: true
published: '2026-11-03'
updated: '2026-11-03'
sourceUpdated: '2026-11-03T21:31:07.998Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63475'
references:
  - url: >-
      https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-96wc-2m84-2cj7
    label: >-
      https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-96wc-2m84-2cj7
  - 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
  - exploit-available
epss: 0.00398
epssPercentile: 0.34215
ingestedAt: '2026-11-05T20:33:06.526Z'
---

## Overview

isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git persists server-supplied circular symref= capabilities through updateRemoteRefs, and GitRefManager.resolve() follows the resulting loose symbolic references without a default depth limit or cycle detection. After a clone from a malicious or man-in-the-middle-controlled remote, operations such as log, status, checkout, and branch that resolve refs/remotes/origin/a or refs/remotes/origin/b do not terminate. The circular references remain on disk, leaving the repository unusable for the application and causing a persistent denial of service. 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.