Private repository name disclosure via validation errors
Published Apr 21, 2026 · Updated Apr 21, 2026
Improper authorization in GitHub Enterprise Server before 3.21 allows remote authenticated users to disclose private repository names. The mobile upload policy API validates a numeric repository ID before checking access, then embeds the inaccessible repository’s full name in an error message. Any authenticated account that can submit IDs to this endpoint can enumerate names, but the flaw does not disclose repository contents or permit modification.
Summary
What happened
Improper authorization in GitHub Enterprise Server before 3.21 allows remote authenticated users to disclose private repository names. The mobile upload policy API validates a numeric repository ID before checking access, then embeds the inaccessible repository’s full name in an error message. Any authenticated account that can submit IDs to this endpoint can enumerate names, but the flaw does not disclose repository contents or permit modification.
The record
- CVE
- CVE-2026-5512
- Published
- Apr 21, 2026
- Updated
- Apr 21, 2026
- Vendor
- Product
- GitHub Enterprise Server
- Classifications
- CWE-201, CAPEC-113
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 21, 2026CVE publishedPublication date reported by the CVE source.
- Apr 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.14.0 <=3.14.25 changes=[{"at":"3.14.26","status":"unaffected"}]
- Affected versionversion=3.15.0 <=3.15.20 changes=[{"at":"3.15.21","status":"unaffected"}]
- Affected versionversion=3.16.0 <=3.16.16 changes=[{"at":"3.16.17","status":"unaffected"}]
- Affected versionversion=3.17.0 <=3.17.13 changes=[{"at":"3.17.14","status":"unaffected"}]
- Affected versionversion=3.18.0 <=3.18.7 changes=[{"at":"3.18.8","status":"unaffected"}]
- Affected versionversion=3.19.0 <=3.19.4 changes=[{"at":"3.19.5","status":"unaffected"}]
- Affected versionversion=3.20.0 <3.20.1 changes=[{"at":"3.20.1","status":"unaffected"}]
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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