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Enterprise ServerApplication · GitHub

CVE-2026-5845

CRITICAL · 9.6 CVSS v3.1 Published 2026-04-21
Fix available
A fix is available. Upgrade to 3.14.26 / 3.15.21 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An improper authorization vulnerability in scoped user-to-server (ghu_) token authorization in GitHub Enterprise Server allows an authenticated attacker to access private repositories outside the intended installation scope, which can include write operations, via an authorization fallback that treated a revoked/deleted installation as a global installation context, which could be chained with token revocation timing and SSH push attribution to obtain and reuse a victim-scoped token. 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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Improper authorization vulnerability in GitHub Enterprise Server's scoped user-to-server (ghu_) token authorization. When an app installation is revoked or deleted, the authorization fallback incorrectly treats it as a global installation context instead of properly rejecting the request, allowing authenticated attackers to access private repositories outside their intended installation scope, including write operations. This can be chained with token revocation timing and SSH push attribution to obtain and reuse victim-scoped tokens.

MitigationUpgrade GitHub Enterprise Server to fixed versions (3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, or 3.14.26) or later. Review access logs for any unauthorized repository access using scoped tokens around installation revocation events.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Enterprise ServerApplication
Affected:< 3.14.26>= 3.15.0, < 3.15.21>= 3.16.0, < 3.16.17>= 3.17.0, < 3.17.14>= 3.18.0, < 3.18.8>= 3.19.0, < 3.19.5= 3.20.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed GitHub Enterprise Server version
    Access the GitHub Enterprise Server management console or run 'ghe-version' command via SSH to the appliance. Alternatively, check the /usr/local/etc/github enterprise version file if available.
    Affected if The installed version falls into any of these ranges: < 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, or equals exactly 3.20.0.
  2. Confirm use of GitHub Apps with scoped tokens
    Review the GitHub Enterprise Server for installed GitHub Apps that generate scoped user-to-server tokens (ghu_ tokens). Check the organization or enterprise settings under 'GitHub Apps' to list active installations.
    Affected if Any GitHub App installations exist that utilize scoped user-to-server authorization tokens.
  3. Review audit logs for installation revocation or deletion events
    Navigate to the organization or enterprise audit log and query for events such as 'installation_deleted', 'installation_revoked', or similar GitHub App installation removal events. Filter by date range and correlate with any suspicious activity.
    Affected if GitHub App installations were revoked or deleted, and subsequent API actions were performed using tokens associated with those installations.
  4. Examine repository access logs for out-of-scope operations
    Search the GitHub Enterprise Server audit logs for repository operations (read, write, push) performed by users or apps where the access may exceed the original installation scope. Look for operations on repositories not originally authorized for the specific app installation.
    Affected if Repository operations occur using scoped tokens on repositories outside the original installation scope, particularly after installation revocation events.

You are affected if your GitHub Enterprise Server version is within the vulnerable ranges AND you have GitHub Apps installed that use scoped user-to-server tokens, with potential exposure during installation revocation events.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.14.26 / 3.15.21 / 3.16.17 or later
Fixed in 3.14.263.15.213.16.17
Interim mitigation

Upgrade GitHub Enterprise Server to fixed versions (3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, or 3.14.26) or later. Review access logs for any unauthorized repository access using scoped tokens around installation revocation events.

Recommended fix High confidence

Upgrade to version 3.14.26 (if on 3.14.x), 3.15.21 (if on 3.15.x), 3.16.17 (if on 3.16.x), 3.17.14 (if on 3.17.x), or preferably the latest stable releases 3.18.8, 3.19.5, or 3.20.1

  1. 1. Identify current GitHub Enterprise Server version by navigating to the Management Console or running: ghe-version
  2. 2. Review the upgrade path - determine which release branch you're on (3.14.x, 3.15.x, 3.16.x, or 3.17.x)
  3. 3. Create a full backup of the GitHub Enterprise Server instance including database and configuration
  4. 4. Schedule a maintenance window as upgrades require downtime
  5. 5. Download the appropriate fixed version for your release branch from github.com/enterprise
  6. 6. Run the upgrade command: ghe-upgrade <path-to-upgrade-package>.pkg or .deb depending on your installation
  7. 7. After upgrade completes, verify the version: ghe-version
  8. 8. Test critical functionality including authentication, repository access, and token-based operations
Caveat Patch releases typically have no breaking changes but always review release notes before upgrading; test in staging environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Enterprise Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-5845 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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