CVE-2026-5512: CWE-201 Insertion of sensitive information into sent data in GitHub Enterprise Server
CVE-2026-5512 is an improper authorization vulnerability in GitHub Enterprise Server that allowed authenticated users to discover private repository names by their numeric IDs. The issue occurred because the mobile upload policy API endpoint did not perform early authorization checks, and validation error messages leaked full repository names for repositories the caller was unauthorized to access. This vulnerability affected all GitHub Enterprise Server versions prior to 3. 21 and was fixed in multiple patch releases starting with versions 3. 14. 26 through 3. 20. 1. The vulnerability was reported through the GitHub Bug Bounty program and has a medium severity rating with a CVSS score of 5. 3.
AI Analysis
Technical Summary
An improper authorization vulnerability (CWE-201) in GitHub Enterprise Server allowed authenticated attackers to enumerate private repository names by their numeric IDs due to insufficient early authorization checks in the mobile upload policy API endpoint. Validation error messages included full repository names even when the caller lacked access permissions. This information disclosure flaw affected all versions prior to 3.21 and was addressed in patch releases 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5, and 3.20.1. The vulnerability was responsibly disclosed via GitHub's Bug Bounty program.
Potential Impact
The vulnerability allows an authenticated attacker to gain knowledge of private repository names that they should not have access to by exploiting error message disclosures. This information disclosure could aid in further targeted attacks or reconnaissance but does not directly allow unauthorized access or modification of repository contents. There are no reports of active exploitation in the wild.
Mitigation Recommendations
Fixes for this vulnerability are available in GitHub Enterprise Server versions 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5, and 3.20.1. Users should upgrade to one of these patched versions or later to remediate the issue. Since this is not a cloud service, remediation depends on applying these official patches. Patch status is confirmed by the vendor advisory embedded in the description.
CVE-2026-5512: CWE-201 Insertion of sensitive information into sent data in GitHub Enterprise Server
Description
CVE-2026-5512 is an improper authorization vulnerability in GitHub Enterprise Server that allowed authenticated users to discover private repository names by their numeric IDs. The issue occurred because the mobile upload policy API endpoint did not perform early authorization checks, and validation error messages leaked full repository names for repositories the caller was unauthorized to access. This vulnerability affected all GitHub Enterprise Server versions prior to 3. 21 and was fixed in multiple patch releases starting with versions 3. 14. 26 through 3. 20. 1. The vulnerability was reported through the GitHub Bug Bounty program and has a medium severity rating with a CVSS score of 5. 3.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
An improper authorization vulnerability (CWE-201) in GitHub Enterprise Server allowed authenticated attackers to enumerate private repository names by their numeric IDs due to insufficient early authorization checks in the mobile upload policy API endpoint. Validation error messages included full repository names even when the caller lacked access permissions. This information disclosure flaw affected all versions prior to 3.21 and was addressed in patch releases 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5, and 3.20.1. The vulnerability was responsibly disclosed via GitHub's Bug Bounty program.
Potential Impact
The vulnerability allows an authenticated attacker to gain knowledge of private repository names that they should not have access to by exploiting error message disclosures. This information disclosure could aid in further targeted attacks or reconnaissance but does not directly allow unauthorized access or modification of repository contents. There are no reports of active exploitation in the wild.
Mitigation Recommendations
Fixes for this vulnerability are available in GitHub Enterprise Server versions 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5, and 3.20.1. Users should upgrade to one of these patched versions or later to remediate the issue. Since this is not a cloud service, remediation depends on applying these official patches. Patch status is confirmed by the vendor advisory embedded in the description.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_P
- Date Reserved
- 2026-04-03T18:21:52.907Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e7faaa19fe3cd2cd0014af
Added to database: 4/21/2026, 10:31:06 PM
Last enriched: 4/21/2026, 10:46:42 PM
Last updated: 4/22/2026, 1:39:06 AM
Views: 7
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