CVE-2026-6736: An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthentica

Routine

MEDIUM 6.5REMOTEUPGRADE

CVE-2026-6736 is a medium-severity flaw (CVSS 6.5) affecting enterprise server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account, bypassing the configured external identity provider. When external authentication was enabled, the signup endpoint did not properly enforce the authentication restriction, allowing account creation and session establishment without identity provider validation. The created account was limited t

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-306
Published	2026-05-07
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

2026-05-07 22:16 UTCPublished CVE record published
2026-10-26 20:10 UTCUpdated Record last modified

github enterprise server UPGRADE

Affected: < 3.16.18 · >= 3.17.0 and < 3.17.15 · >= 3.18.0 and < 3.18.9 · >= 3.19.0 and < 3.19.6 · >= 3.20.0 and < 3.20.2

Fixed in: 3.16.18, 3.17.15, 3.18.9, 3.19.6, 3.20.2

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 3.16.18 (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-2026-6736?

enterprise server: upgrade to 3.16.18, 3.17.15, 3.18.9, 3.19.6, 3.20.2. Exact commands for each OS are on this page.

Is CVE-2026-6736 being exploited?

CVE-2026-6736 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-2026-6736 affect?

CVE-2026-6736 affects enterprise server. Severity is medium (CVSS 6.5). An authentication bypass vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to create a local user account, bypassing the configured external identity provider. When external authentication was

How urgent is CVE-2026-6736?

Priority 32/100. Remotely exploitable, no login, no user action

Software pages

GitHub vulnerabilities

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References

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