CVE-2026-15996 Denial of service in Enterprise Server

Medium 6.6 Published 5 Aug 2026 Updated 6 Aug 2026

Unauthenticated attackers can cause denial of service in GitHub Enterprise Server by sending crafted requests with deeply nested parameters, exhausting worker processes.

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

What is CVE-2026-15996?

CVE-2026-15996 is a medium-severity denial of service vulnerability in Github Enterprise Server, published on 5 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A denial of service vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to cause excessive CPU consumption and exhaust the pool of request-handling worker processes by sending a crafted form-encoded HTTP POST request containing deeply nested parameters. Because request parameters were parsed before routing and authentication, any POST endpoint could be used to trigger the condition, which could render the instance unresponsive. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.3, 3.19.7, 3.18.10, and 3.17.16.

Weakness: CWE-674

Which versions are affected by CVE-2026-15996?

It affects 1 product.

Products include Github Enterprise Server.

How do I fix CVE-2026-15996?

No fix has been published for CVE-2026-15996 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-15996 being exploited?

There is no known exploitation of CVE-2026-15996 in the wild and no public exploit code.

All Github Enterprise Server vulnerabilities

Sources

Also known as GHSA-3x3p-rpwc-h9wf.