CVE-2026-5512: An improper authorization vulnerability was identified in GitHub Enterprise Server that allowed an authenticat

Routine

MEDIUM 4.3UPGRADE

CVE-2026-5512 is a medium-severity flaw (CVSS 4.3) affecting enterprise server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 Enterpris

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 78%)
CISA exploited list	No
Weakness	CWE-201
Published	2026-04-21
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. (Products Only) · Vendor: github

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-21 23:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

github enterprise server UPGRADE

Affected: < 3.14.26 · >= 3.15.0 and < 3.15.21 · >= 3.16.0 and < 3.16.17 · >= 3.17.0 and < 3.17.14 · >= 3.18.0 and < 3.18.8 · >= 3.19.0 and < 3.19.5 · 3.20.0

Fixed in: 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5

Safe to downgrade to: a release before 3.15.0

1. Check installed version

apt-cache policy enterprise-server || rpm -q enterprise-server || enterprise-server --version

2. UPGRADE to 3.14.26 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade enterprise-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade enterprise-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.15.0 (Debian / Ubuntu)

apt-cache madison enterprise-server sudo apt install enterprise-server=<VERSION_BEFORE_3.15.0> sudo apt-mark hold enterprise-server

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list enterprise-server sudo dnf downgrade enterprise-server-<VERSION_BEFORE_3.15.0> sudo dnf versionlock add enterprise-server

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-5512?

enterprise server: upgrade to 3.14.26, 3.15.21, 3.16.17, 3.17.14, 3.18.8, 3.19.5. Exact commands for each OS are on this page.

Is CVE-2026-5512 being exploited?

CVE-2026-5512 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-5512 affect?

CVE-2026-5512 affects enterprise server. Severity is medium (CVSS 4.3). 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 perf

How urgent is CVE-2026-5512?

Priority 21/100. No elevated risk signals yet.

Software pages

GitHub vulnerabilities

Related CVEs

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References

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