# CVE-2026-15996: Denial of service vulnerability in GitHub Enterprise Server allowed unauthenticated service disruption via deeply nested request parameters

> CVE-2026-15996: Denial of service vulnerability in GitHub Enterprise Server allowed unauthenticated service disruption via deeply nested request parameters. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-15996
Last updated: 2026-10-23T21:10:00Z

- Published: 2026-08-05 20:12 UTC · Updated: 2026-10-23 21:10 UTC · Assigner: GitHub\_P
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS: 0.77%, 55th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-674

## 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.

## Affected vendors and products

- GitHub: Enterprise Server

## Tracked companies

- [GitHub](https://rewindex.com/company/github.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-15996)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-15996)
- [https://docs.github.com/en/enterprise-server@3.17/admin/release-notes\#3.17.16](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@3.18/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@3.19/admin/release-notes#3.19.7)
- [https://docs.github.com/en/enterprise-server@3.20/admin/release-notes\#3.20.3](https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.3)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-15996 · Markdown: https://rewindex.com/cve/CVE-2026-15996.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-15996 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:17:04.715Z