---
id: CVE-2026-89011
title: >-
  isomorphic-git before 1.42.0 contains a prototype pollution vulnerability in
  the getRemoteInfo function that allows a malicious Git server operator to
  pollute Object.prototype by advertising crafted ref names containing
  '__proto__' path …
summary: >-
  isomorphic-git before 1.42.0 contains a prototype pollution vulnerability in
  the getRemoteInfo function that allows a malicious Git server operator to
  pollute Object.prototype by advertising crafted ref names containing
  '__proto__' path …
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N'
cwe:
  - CWE-1321
vendor: isomorphic-git
product: isomorphic-git
affected:
  - isomorphic-git < 1.42.0
published: '2026-09-10'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T17:17:46.310'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89011'
references:
  - url: >-
      https://github.com/isomorphic-git/isomorphic-git/commit/b3db111885230bac9a648e0a2312c65ca66f76eb
    label: disclosure@vulncheck.com
  - url: 'https://github.com/isomorphic-git/isomorphic-git/pull/2426'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.42.0'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-83vg-jxvh-fx76
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/isomorphic-git-prototype-pollution-via-getremoteinfo
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
epss: 0.00443
epssPercentile: 0.35775
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-11T17:09:25.363378Z'
ingestedAt: '2026-09-14T11:11:19.881Z'
---

## Overview

isomorphic-git before 1.42.0 contains a prototype pollution vulnerability in the getRemoteInfo function that allows a malicious Git server operator to pollute Object.prototype by advertising crafted ref names containing '__proto__' path segments during ref negotiation. Attackers controlling a Git server can advertise a specially crafted ref such as '__proto__/corsProxy' to reroute all subsequent network operations through an attacker-controlled proxy, causing isomorphic-git to invoke the victim's onAuth callback and transmit credentials to the attacker when the victim calls getRemoteInfo with an attacker-supplied URL.

## Remediation

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