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CVE

CVE-2026-5512

An improper authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticated attacke

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.

MEDIUM · CVSS 4.3 EPSS 0.00038
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-201Insertion of Sensitive Information Into Sent Data
▤

Affected Products & Versions

7
github enterprise server< 3.14.26
github enterprise server>= 3.15.0 and < 3.15.21
github enterprise server>= 3.16.0 and < 3.16.17
github enterprise server>= 3.17.0 and < 3.17.14
github enterprise server>= 3.18.0 and < 3.18.8
github enterprise server>= 3.19.0 and < 3.19.5
github enterprise serverall versions
▣

Scoring & Timeline

4.3
MEDIUM · CVSS v3.1 · product-cna@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD21 Apr 2026 · 11:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

7
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://docs.github.com/en/enterprise-server@3.14/admin/release-notes#3.14.26Release NotesVendor Advisory
https://docs.github.com/en/enterprise-server@3.15/admin/release-notes#3.15.21Release NotesVendor Advisory
https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.17Release NotesVendor Advisory
https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.14Release NotesVendor Advisory
https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.8Release NotesVendor Advisory
https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.5Release NotesVendor Advisory
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