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

High 7.7 Published 1 Sep 2026 Updated 2 Sep 2026

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

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

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

Which versions are affected by CVE-2026-76851?

It affects 1 product.

Products include 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.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-76851 being exploited?

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

All Github Enterprise Server vulnerabilities

Sources

Also known as GHSA-hp6r-mrh8-47vq.