CVE-2026-5512

Medium

Description

An improper authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated attacker to determine the names of private repositories by their numeric ID. The mobile upload policy API endpoint did not perform an early authorization check, and validation error messages included the full repository name for repositories the caller did not have access to. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, and 3.14.26. This vulnerability was reported via the GitHub Bug Bounty program.

SeverityMedium
CVSS4.3
Exploit probability—
ProductGithub Enterprise Server
PublishedApr 21, 2026
First seenApr 21, 2026
Weakness typeCWE-201CWE-201

How to fix

Update
  • github enterprise_server3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5 or later

Affected products

ProductAffected versionsFixed in
github enterprise_serverv < 3.14.26, 3.15.0 ≤ v < 3.15.21, 3.16.0 ≤ v < 3.16.17, 3.17.0 ≤ v < 3.17.14, 3.18.0 ≤ v < 3.18.8, 3.19.0 ≤ v < 3.19.5, 3.20.03.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5

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