---
id: CVE-2026-76851
title: >-
  A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub
  Enterprise Server that allowed remote code execution on the instance
summary: >-
  A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub
  Enterprise Server that allowed remote code execution on the instance.
  Insufficient network isolation allowed malicious pre-receive hook code to
  impersonate an in…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-918
vendor: github
product: enterprise_server
affected:
  - enterprise_server < 3.17.20
  - 'enterprise_server >= 3.18.0, < 3.18.14'
  - 'enterprise_server >= 3.19.0, < 3.19.11'
  - 'enterprise_server >= 3.20.0, < 3.20.7'
  - 'enterprise_server >= 3.21.0, < 3.21.5'
patched:
  - enterprise_server 3.21.5
published: '2026-09-01'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T13:05:37.213'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-76851'
references:
  - url: >-
      https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.20
    label: product-cna@github.com
  - url: >-
      https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.14
    label: product-cna@github.com
  - url: >-
      https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.11
    label: product-cna@github.com
  - url: >-
      https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.7
    label: product-cna@github.com
  - url: >-
      https://docs.github.com/en/enterprise-server@3.21/admin/release-notes#3.21.5
    label: product-cna@github.com
tags:
  - nvd
epss: 0.00829
epssPercentile: 0.55729
ingestedAt: '2026-09-08T15:33:26.957Z'
---

## Overview

A Server-Side Request Forgery (SSRF) vulnerability was identified in GitHub Enterprise Server that allowed remote code execution on the instance. Insufficient network isolation allowed malicious pre-receive hook code to impersonate an internal service and redirect trusted internal requests to a privileged service, leading to elevated code execution. Exploitation required pre-receive hook networking to be enabled and either site administrator privileges or write access to a repository containing a configured pre-receive hook. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.22 and was fixed in versions 3.17.20, 3.18.14, 3.19.11, 3.20.7, and 3.21.5. This vulnerability was reported via the GitHub Bug Bounty program.

## Affected

- `enterprise_server < 3.17.20`
- `enterprise_server >= 3.18.0, < 3.18.14`
- `enterprise_server >= 3.19.0, < 3.19.11`
- `enterprise_server >= 3.20.0, < 3.20.7`
- `enterprise_server >= 3.21.0, < 3.21.5`

## Remediation

Upgrade past the affected range:

- `enterprise_server 3.21.5`