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Vulnerability record · CVE-2021-22863 · published 3 March 2021

CVE-2021-22863: Github improper authorization vulnerability

Github · Github

An improper access control vulnerability was identified in the GitHub Enterprise Server GraphQL API that allowed authenticated users of the instance to modify the maintainer collaboration permission of a pull request without proper authorization. By exploiting this vulnerability, an attacker would be able to gain access to head branches of pull requests opened on repositories of which they are a maintainer. Forking is disabled by default for organization owned private repositories and would prevent this vulnerability. Additionally, branch protections such as required pull request reviews or status checks would prevent unauthorized commits from being merged without further review or validation. This vulnerability affected all versions of GitHub Enterprise Server since 2.12.22 and was fixed in versions 2.20.24, 2.21.15, 2.22.7 and 3.0.1. This vulnerability was reported via the GitHub Bug Bounty program.

8.1 CVSS 3.1 High EPSS 1.0% · top 38.5% CWE-285 · Improper authorization
8.1CVSS 3.1 base score, v2 5.5
1.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

Description

An improper access control vulnerability was identified in the GitHub Enterprise Server GraphQL API that allowed authenticated users of the instance to modify the maintainer collaboration permission of a pull request without proper authorization. By exploiting this vulnerability, an attacker would be able to gain access to head branches of pull requests opened on repositories of which they are a maintainer. Forking is disabled by default for organization owned private repositories and would prevent this vulnerability. Additionally, branch protections such as required pull request reviews or status checks would prevent unauthorized commits from being merged without further review or validation. This vulnerability affected all versions of GitHub Enterprise Server since 2.12.22 and was fixed in versions 2.20.24, 2.21.15, 2.22.7 and 3.0.1. This vulnerability was reported via the GitHub Bug Bounty program.

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

Affected products

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

References

LinkTags
https://docs.github.com/en/enterprise-server%402.20/admin/release-notes#2.20.24
https://docs.github.com/en/enterprise-server%402.21/admin/release-notes#2.21.15
https://docs.github.com/en/enterprise-server%402.22/admin/release-notes#2.22.7
https://docs.github.com/en/enterprise-server%403.0/admin/release-notes#3.0.1
https://docs.github.com/en/enterprise-server%402.20/admin/release-notes#2.20.24
https://docs.github.com/en/enterprise-server%402.21/admin/release-notes#2.21.15
https://docs.github.com/en/enterprise-server%402.22/admin/release-notes#2.22.7
https://docs.github.com/en/enterprise-server%403.0/admin/release-notes#3.0.1

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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-2021-22863), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.