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

Summary

CVECVE-2026-5512
StatePUBLISHED
AssignerGitHub_P
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-21 23:16:22 UTC
Updated2026-04-22 21:23:52 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v4.0 5.3 MEDIUM from [email protected]

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

EPSS: 0.000500000 probability, percentile 0.154920000 (date 2026-04-22)

Problem Types: CWE-201 | CWE-201 CWE-201 Insertion of sensitive information into sent data


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary5.3MEDIUMCVSS: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/C...
4.0CNACVSS5.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:L/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Sub Conf.
None
Sub Integrity
Low
Sub Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA GitHub Enterprise Server affected 3.14.0 3.14.25 semver Not specified
CNA GitHub Enterprise Server affected 3.15.0 3.15.20 semver Not specified
CNA GitHub Enterprise Server affected 3.16.0 3.16.16 semver Not specified
CNA GitHub Enterprise Server affected 3.17.0 3.17.13 semver Not specified
CNA GitHub Enterprise Server affected 3.18.0 3.18.7 semver Not specified
CNA GitHub Enterprise Server affected 3.19.0 3.19.4 semver Not specified
CNA GitHub Enterprise Server affected 3.20.0 3.20.1 semver Not specified

References

ReferenceSourceLinkTags
docs.github.com/en/[email protected]/admin/release-notes [email protected] docs.github.com
docs.github.com/en/[email protected]/admin/release-notes [email protected] docs.github.com
docs.github.com/en/[email protected]/admin/release-notes [email protected] docs.github.com
docs.github.com/en/[email protected]/admin/release-notes [email protected] docs.github.com
docs.github.com/en/[email protected]/admin/release-notes [email protected] docs.github.com
docs.github.com/en/[email protected]/admin/release-notes [email protected] docs.github.com
docs.github.com/en/[email protected]/admin/release-notes [email protected] docs.github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: ahacker1 (en)

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