# CVE-2026-76851: Server-side request forgery in Enterprise Server

> Attacker with hook access exploits SSRF to execute code on GitHub Enterprise Server by bypassing network isolation.

- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 1 Sep 2026
- **Updated:** 2 Sep 2026
- **Also known as:** GHSA-hp6r-mrh8-47vq

## What is CVE-2026-76851?

CVE-2026-76851 is a high-severity server-side request forgery vulnerability in Github Enterprise Server, published on 1 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-76851?

It affects 1 product.


Products: Github Enterprise Server.

## How do I fix CVE-2026-76851?

No fix has been published for CVE-2026-76851 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76851 being exploited?

There is no known exploitation of CVE-2026-76851 in the wild and no public exploit code.

## Other vulnerabilities in Github Enterprise Server

- [CVE-2024-4985](https://insights.sbomify.com/CVE-2024-4985/): Auth bypass in Enterprise Server (critical 10.0)
- [CVE-2022-23739](https://insights.sbomify.com/CVE-2022-23739/): Missing authorization in GitHub Enterprise Server (critical 9.8)
- [CVE-2022-46255](https://insights.sbomify.com/CVE-2022-46255/): Improper Limitation of a Pathname to a Restricted Directory in GitHub Enterprise Server leading to RCE (critical 9.8)
- [CVE-2021-22869](https://insights.sbomify.com/CVE-2021-22869/): Improper access control in GitHub Enterprise Server allows self-hosted runners to execute outside their control group (critical 9.8)
- [CVE-2024-9487](https://insights.sbomify.com/CVE-2024-9487/): Auth bypass in Enterprise Server (critical 9.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76851 and fix it if it is affected.

What it is: CVE-2026-76851 is a high-severity server-side request forgery vulnerability in Github Enterprise Server, published on 1 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76851 in the wild and no public exploit code.

Affected product: Github Enterprise Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-76851/ (Markdown: https://insights.sbomify.com/CVE-2026-76851/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76851
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76851
- OSV: https://osv.dev/vulnerability/CVE-2026-76851

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-76851/
Summaries are generated and may contain mistakes; the official description above is the record.