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CVE-2026-5512EXPLOITEDPATCHED
github · github enterprise

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

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

VendorProductVersions
githubgithub enterprise3.14.0, 3.15.0, 3.16.0, 3.17.0, 3.18.0, 3.19.0, 3.20.0

Also Affects

Downstream vendors/products affected by this vulnerability

VendorProductSourceConfidence
microsoftgithub enterprisecert_advisory90%

References

  • https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.26
  • https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21
  • https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17
  • https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14
  • https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8
  • https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.5
  • https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1

Related News (2 articles)

Tier B
BSI Advisories11d ago
[NEU] [hoch] Microsoft GitHub Enterprise: Mehrere Schwachstellen
→ No new info (linked only)
Tier C
VulDB11d ago
CVE-2026-5512 | GitHub Enterprise Server up to 3.20.0 API Endpoint insertion of sensitive information into sent data
→ No new info (linked only)
CISA KEV❌ No
Actively exploited✅ Yes
Patch available
3.20.1
CWECWE-201
PublishedApr 21, 2026
Last enriched11d agov2
Trending Score9
Source articles2
Independent2
Info Completeness8/14
Missing: cvss, epss, kev, exploit, iocs, mitre_attack

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Related CVEs (5)

CRITICALCVE-2026-3854
Remote code execution via git push option injection in GitHub Enterprise Server
Trending: 66
HIGHCVE-2026-4821EXP
Proxy configuration command injection vulnerability found in GitHub Enterprise Server Management Console configuration API
Trending: 14
NONECVE-2026-5921
Server-Side Request Forgery in GitHub Enterprise Server allowed extraction of sensitive environment variables via timing side-channel attack
Trending: 9
NONECVE-2026-4296
Incorrect Regular Expression vulnerability in GitHub Enterprise Server allowed unauthorized access to user accounts via OAuth callback URL validation bypass
Trending: 9
NONECVE-2026-5845
Improper authorization fallback allows scoped user-to-server token installation escape in GitHub Enterprise Server
Trending: 9

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Verification

State: unverified
Confidence: 0%

Vulnerability Timeline

CVE Published
Apr 21, 2026
Discovered by ZDM
Apr 21, 2026
Updated: description, severity, activelyExploited
Apr 22, 2026
Actively Exploited
Apr 22, 2026
Patch Available
Apr 22, 2026

Version History

v2
Last enriched 11d ago
v2Tier C11d ago

Updated description with new technical details, changed severity to HIGH, marked as actively exploited, and noted no exploit available.

descriptionseverityactivelyExploited
via VulDB
v111d ago

Initial creation