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Vulnerability record · CVE-2026-15996 · published 5 August 2026

CVE-2026-15996: Github enterprise server vulnerability

Github · Enterprise Server

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.

6.6 CVSS 4.0 Medium EPSS 0.77% · top 46.3% CWE-674 · CWE-674
6.6CVSS 4.0 base score
0.77%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
18 Aug 2026Last modified by NVD

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.

CVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://docs.github.com/en/[email protected]/admin/release-notes#3.17.16 ProductRelease Notes
https://docs.github.com/en/[email protected]/admin/release-notes#3.18.10 ProductRelease Notes
https://docs.github.com/en/[email protected]/admin/release-notes#3.19.7 ProductRelease Notes
https://docs.github.com/en/[email protected]/admin/release-notes#3.20.3 ProductRelease Notes

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-15996), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.