CVE-2021-22865: Improper access control in GitHub Enterprise Server leading to unauthorized read access to private repository metadata

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-04-02 · updated 2026-06-17
Weakness: CWE-285

Description

An improper access control vulnerability was identified in GitHub Enterprise Server that allowed access tokens generated from a GitHub App's web authentication flow to read private repository metadata via the REST API without having been granted the appropriate permissions. To exploit this vulnerability, an attacker would need to create a GitHub App on the instance and have a user authorize the application through the web authentication flow. The private repository metadata returned would be limited to repositories owned by the user the token identifies. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.0.4 and was fixed in versions 3.0.4, 2.22.10, 2.21.18. This vulnerability was reported via the GitHub Bug Bounty program.

Affected products

GitHub Enterprise Server: before 2.21.18; from 2.22.0 before 2.22.10; from 3.0.0 before 3.0.4 — fixed in 2.21.18, 2.22.10, 3.0.4

How to fix

Upgrade to a fixed version: GitHub Enterprise Server 2.21.18, 2.22.10, 3.0.4. Check the vendor advisory for mitigations.

References

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