EUVD-2026-24550
GHSA-28fv-vpxc-gmp4
Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-accessible API requires only low-privilege authentication (PR:L); only private repository names are disclosed, yielding low confidentiality impact with no integrity or availability consequence.
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
5DescriptionGitHub Advisory
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.
AnalysisAI
Private repository name disclosure in GitHub Enterprise Server allows any authenticated user to enumerate the names of private repositories by their numeric ID via a missing authorization check in the mobile upload policy API endpoint. Validation error responses included full repository names even when the requesting user lacked access to those repositories. No public exploit has been identified, EPSS is 0.05% (15th percentile), SSVC rates exploitation as none, and this was responsibly disclosed through the GitHub Bug Bounty program - indicators that real-world risk is low but the confidentiality impact is meaningful in environments with sensitive project naming conventions.
Technical ContextAI
GitHub Enterprise Server (CPE: cpe:2.3:a:github:enterprise_server) is GitHub's self-hosted product for enterprises. The vulnerability is rooted in CWE-201 (Insertion of Sensitive Information Into Sent Data): a mobile upload policy REST API endpoint omitted an early authorization gate, allowing the request to proceed far enough into processing that validation error messages were generated using the full, resolved repository name - a name the caller was not authorized to see. The underlying flaw is an improper authorization ordering issue where resource resolution precedes access control, causing sensitive metadata to surface in error responses. The numeric repository ID acts as an oracle: an attacker iterates IDs, observes error message content, and reconstructs private repository names without ever gaining access to repository contents.
RemediationAI
Vendor-released patches are available across all supported branches: upgrade to 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, or 3.14.26 depending on the installed branch. Release notes confirming the fix are available at the branch-specific GitHub documentation pages (e.g., https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.1 and corresponding pages for other branches). No workarounds have been identified that address the root cause without patching - network-level blocking of the mobile upload policy API endpoint could prevent exploitation but may break legitimate mobile upload functionality. Organizations unable to patch immediately should assess whether mobile upload functionality is in use and whether exposure to untrusted authenticated users warrants temporary disablement of that endpoint.
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External POC / Exploit Code
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