Vulnerability Monitor

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CVE-2026-5512

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.

Security Impact Summary

This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 4.3, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction requiring only low-level privileges . The vulnerability impacts limited data confidentiality, for affected systems. Impacting 1 product from github organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2026-04-21T23:16:22.297

Last Modified

2026-04-29T12:35:08.490

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 4.3 (MEDIUM)

Weaknesses

Type: Secondary
CWE-201

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	github	enterprise_server	< 3.14.26	Yes
Application	github	enterprise_server	< 3.15.21	Yes
Application	github	enterprise_server	< 3.16.17	Yes
Application	github	enterprise_server	< 3.17.14	Yes
Application	github	enterprise_server	< 3.18.8	Yes
Application	github	enterprise_server	< 3.19.5	Yes
Application	github	enterprise_server	3.20.0	Yes

References

https://docs.github.com/en/[email protected]/admin/release-notes#3.14.26 Release Notes, Vendor Advisory ([email protected])
https://docs.github.com/en/[email protected]/admin/release-notes#3.15.21 Release Notes, Vendor Advisory ([email protected])
https://docs.github.com/en/[email protected]/admin/release-notes#3.16.17 Release Notes, Vendor Advisory ([email protected])
https://docs.github.com/en/[email protected]/admin/release-notes#3.17.14 Release Notes, Vendor Advisory ([email protected])
https://docs.github.com/en/[email protected]/admin/release-notes#3.18.8 Release Notes, Vendor Advisory ([email protected])
https://docs.github.com/en/[email protected]/admin/release-notes#3.19.5 Release Notes, Vendor Advisory ([email protected])
https://docs.github.com/en/[email protected]/admin/release-notes#3.20.1 Release Notes, Vendor Advisory ([email protected])

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For github's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.