CVE-2026-15996

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.

CVSS 4.0

6.6CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.8% chance of exploitation in the next 30 days; higher than 55% of CVEs (scores of 2026-10-25)

CWE

CWE-674

Published

2026-08-05

Modified

2026-10-23

Record from

the NVD, synced 2026-10-24

Affected

• github:enterprise_server

References

• https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.16
• https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.10
• https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.7
• https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.3

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