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Vulnerability record · CVE-2021-22861 · published 3 March 2021

CVE-2021-22861: Github improper authorization vulnerability

Github · Github

An improper access control vulnerability was identified in GitHub Enterprise Server that allowed authenticated users of the instance to gain write access to unauthorized repositories via specifically crafted pull requests and REST API requests. An attacker would need to be able to fork the targeted repository, a setting that is disabled by default for organization owned private repositories. 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 2.4.21 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.

6.5 CVSS 3.1 Medium EPSS 0.95% · top 40.2% CWE-285 · Improper authorization
6.5CVSS 3.1 base score, v2 4.0
0.95%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 GitHub Enterprise Server that allowed authenticated users of the instance to gain write access to unauthorized repositories via specifically crafted pull requests and REST API requests. An attacker would need to be able to fork the targeted repository, a setting that is disabled by default for organization owned private repositories. 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 2.4.21 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:N/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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Source: NIST National Vulnerability Database (record CVE-2021-22861), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.