CVE-2021-22861

Improper access control in GitHub Enterprise Server leading to unauthorized write access to forkable repositories

MEDIUM

6.5

CVSS Score

Published: March 3, 2021 at 03:25 AM UTC

Updated: June 17, 2026 at 03:37 AM UTC

2 products affected across 1 vendorGitHubGitHub Enterprise Server

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Severity

MEDIUM6.5

Exploit prediction

EPSS 1.0%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

GitHub · GitHub

95%

2.21.0 ≤ v < 2.21.152.22.0 ≤ v < 2.22.72.4.21 ≤ v < 2.20.243.0.0 ≤ v < 3.0.1

Affected range stops below 2.20.24, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.21.15, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.22.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.0.1, so it looks safe — our inference, not a vendor statement

GitHub Enterprise Server · GitHubgithub-action

60%

2.20 ≤ v < 2.20.242.21 ≤ v < 2.21.152.22 ≤ v < 2.22.73.0 ≤ v < 3.0.12.20 2.21 2.22 3.0

Affected range stops below 2.20.24, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.21.15, so it looks safe — our inference, not a vendor statement

Affected range stops below 2.22.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 3.0.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (4)

x_refsource_MISC

Source: [email protected]

https://docs.github.com/en/enterprise-server%402.20/admin/release-notes#2.20.24

x_refsource_MISC

Source: [email protected]

https://docs.github.com/en/enterprise-server%402.21/admin/release-notes#2.21.15

x_refsource_MISC

Source: [email protected]

https://docs.github.com/en/enterprise-server%402.22/admin/release-notes#2.22.7

x_refsource_MISC

Source: [email protected]

https://docs.github.com/en/enterprise-server%403.0/admin/release-notes#3.0.1

CVSS

6.5MEDIUM[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-285NVD-CWE-Other

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