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Vulnerability · Published Apr 21, 2026 · Assigned by GitHub_P

CVE-2026-5512Improper authorization vulnerability in GitHub Enterprise Server allowed disclosure of private repository names via mobile upload policy API

Medium 5.3

In plain English

A medium-severity security flaw in Enterprise Server from GitHub. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 4.0)5.3Medium
Exploit odds (30 days)0.3%top 77.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

VendorProductVersions
GitHub Enterprise Server 3.14.0 – through 3.14.253.15.0 – through 3.15.203.16.0 – through 3.16.163.17.0 – through 3.17.133.18.0 – through 3.18.73.19.0 – through 3.19.43.20.0 – before 3.20.1

Weakness: CWE-201 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:L/SA:N

References