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Enterprise ServerApplication · GitHub

CVE-2026-1355

MEDIUM · 6.5 CVSS v3.1 Published 2026-02-18
Fix available
A fix is available. Upgrade to 3.14.23 / 3.15.18 or later.
See remediation →
71/100
Remediation priority · Elevated
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
A Missing Authorization vulnerability was identified in GitHub Enterprise Server that allowed an attacker to upload unauthorized content to another user’s repository migration export due to a missing authorization check in the repository migration upload endpoint. By supplying the migration identifier, an attacker could overwrite or replace a victim’s migration archive, potentially causing victims to download attacker-controlled repository data during migration restores or automated imports. An attacker would require authentication to the victim's GitHub Enterprise Server instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.19.2, 3.18.5, 3.17.11, 3.16.14, 3.15.18, 3.14.23. 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

Missing authorization check in GitHub Enterprise Server's repository migration upload endpoint allows authenticated attackers to overwrite victim migration archives by supplying a migration identifier. This enables injection of attacker-controlled data that victims may download during migration restores or automated imports.

MitigationUpgrade GitHub Enterprise Server to version 3.19.2, 3.18.5, 3.17.11, 3.16.14, 3.15.18, or 3.14.23 or later to incorporate the authorization fix.

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:< 3.14.23>= 3.15.0, < 3.15.18>= 3.16.0, < 3.16.14>= 3.17.0, < 3.17.11>= 3.18.0, < 3.18.5>= 3.19.0, < 3.19.2

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
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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 the installed GitHub Enterprise Server version
    Access the GitHub Enterprise Server admin console or run 'ghe-version' in the management shell to retrieve the exact version number.
    Affected if The installed version falls within any of these vulnerable ranges: < 3.14.23, >= 3.15.0 and < 3.15.18, >= 3.16.0 and < 3.16.14, >= 3.17.0 and < 3.17.11, >= 3.18.0 and < 3.18.5, or >= 3.19.0 and < 3.19.2.
  2. Verify repository migration API accessibility
    Check whether the repository migration API endpoints (/api/v3/migrations or similar) are exposed and accessible to authenticated users in the instance.
    Affected if Migration API endpoints are enabled and accessible to non-admin authenticated users.
  3. Review audit logs for migration upload activity
    Search enterprise audit logs for entries related to migration archive uploads, specifically looking for migration identifier parameters that may indicate unauthorized overwrites.
    Affected if Audit logs show migration uploads with migration identifiers that were not created by the requesting user, indicating potential exploitation.

If the GitHub Enterprise Server version is within any of the vulnerable ranges listed, the environment is affected by this missing authorization check in the migration upload endpoint.

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 3.14.23 / 3.15.18 / 3.16.14 or later
Fixed in 3.14.233.15.183.16.14
Interim mitigation

Upgrade GitHub Enterprise Server to version 3.19.2, 3.18.5, 3.17.11, 3.16.14, 3.15.18, or 3.14.23 or later to incorporate the authorization fix.

Recommended fix High confidence

Upgrade to 3.14.23, 3.15.18, 3.16.14, or 3.17.11 (or later) depending on your current version branch; alternatively upgrade to the latest stable release (3.20 or later)

  1. 1. Identify the current GitHub Enterprise Server version by navigating to the admin console or running: ghe-version
  2. 2. Determine which version branch you're currently on based on the major.minor version (e.g., 3.14.x, 3.15.x, 3.16.x, 3.17.x)
  3. 3. Upgrade to the corresponding fixed version for your branch: 3.14.23 (if on 3.14.x), 3.15.18 (if on 3.15.x), 3.16.14 (if on 3.16.x), or 3.17.11 (if on 3.17.x)
  4. 4. For branches 3.18.x and 3.19.x, upgrade to 3.18.5 and 3.19.2 respectively, or preferably the latest available patch for those branches
  5. 5. Follow the standard GitHub Enterprise Server upgrade procedure documented at docs.github.com/en/enterprise-server/admin/install-and-upgrade-upgrading-github-enterprise-server
  6. 6. After upgrade, verify the version with: ghe-version
  7. 7. Test repository migration functionality to confirm the fix is working properly
Caveat Standard GitHub Enterprise Server upgrade considerations apply - review release notes for your target version for any known migration or configuration changes

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

Fix this in Enterprise Server Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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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-2026-1355 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

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