CVE-2021-22863: An improper access control vulnerability was identified in the GitHub Enterprise Server GraphQL API that allowed authenticated users of the instance t...

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.

Metrics

CVSS 3.1

8.1/10

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

EPSS Probability

0.97%

57.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-285

Affected Software

Vendor	Product	Versions
Github	Github	>= 2.12.22, < 2.20.24
Github	Github	>= 2.21.0, < 2.21.15
Github	Github	>= 2.22.0, < 2.22.7
Github	Github	>= 3.0.0, < 3.0.1

References

Timeline

Published: Mar 3, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-22863?

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.

How severe is CVE-2021-22863?

CVE-2021-22863 has a CVSS score of 8.1/10 (HIGH severity). The EPSS model estimates a 0.97% probability of exploitation in the next 30 days.

How do I fix CVE-2021-22863?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.