CVE-2026-14340: An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed a user-to-ser

Routine

MEDIUM 5.0UPGRADE

CVE-2026-14340 is a medium-severity flaw (CVSS 5.0) affecting enterprise server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed a user-to-server token scoped to a GitHub App installation to perform certain write operations on public repositories outside the token's intended scope. This was possible because the authorization check only verified that the installation had read permissions on the target repository rather than verifying that the token's installation was explicitly

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 63%)
CISA exploited list	No
Weakness	CWE-863
Published	2026-07-01
Last modified	2026-10-25

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

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-01 21:16 UTCPublished CVE record published
2026-10-25 16:10 UTCUpdated Record last modified

github enterprise server UPGRADE

Affected: < 3.16.20 · >= 3.17.0 and < 3.17.17 · >= 3.18.0 and < 3.18.11 · >= 3.19.0 and < 3.19.8 · >= 3.20.0 and < 3.20.4 · >= 3.21.0 and < 3.21.2

Fixed in: 3.16.20, 3.17.17, 3.18.11, 3.19.8, 3.20.4, 3.21.2

Safe to downgrade to: a release before 3.17.0

1. Check installed version

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

2. UPGRADE to 3.16.20 (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 3.17.0 (Debian / Ubuntu)

apt-cache madison enterprise-server sudo apt install enterprise-server=<VERSION_BEFORE_3.17.0> 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_3.17.0> 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-2026-14340?

enterprise server: upgrade to 3.16.20, 3.17.17, 3.18.11, 3.19.8, 3.20.4, 3.21.2. Exact commands for each OS are on this page.

Is CVE-2026-14340 being exploited?

CVE-2026-14340 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-2026-14340 affect?

CVE-2026-14340 affects enterprise server. Severity is medium (CVSS 5.0). An incorrect authorization vulnerability was identified in GitHub Enterprise Server that allowed a user-to-server token scoped to a GitHub App installation to perform certain write operations on public repositories outside the token's inten

How urgent is CVE-2026-14340?

Priority 27/100. No elevated risk signals yet.

Software pages

GitHub vulnerabilities

Related CVEs

CVE-2026-17556 CRITICAL 9.1 UPGRADE A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated atta
CVE-2026-15996 HIGH 7.5 UPGRADE A denial of service vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated a

References

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