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Vulnerabilities

Vulnerability · CVE-2026-103620

A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default…

Published Oct 6, 2026 · catalog updated Oct 20, 2026 · enterprise server

Last checked Oct 23, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-103620. EPSS is 0.50%. Act only if a listed version of enterprise server is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.50%
Remediation
Version ranges on file
Affected products
cpe github/enterprise server

A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default branch through the GraphQL API and cause an attacker-controlled branch to become the new default. In repositories that required pull-request review but did not restrict branch deletion, this bypassed the review requirement and caused fresh clones and default-branch API requests to use attacker-controlled content. This vulnerability affected supported GitHub Enterprise Server releases in the 3.18, 3.19, 3.20, 3.21, and 3.22 series and was fixed in versions 3.18.16, 3.19.13, 3.20.9, 3.21.7, and 3.22.2. This vulnerability was reported via the GitHub Bug Bounty program.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe github/enterprise server< 3.18.16
  • cpe github/enterprise server< 3.19.13
  • cpe github/enterprise server< 3.20.9
  • cpe github/enterprise server< 3.21.7
  • cpe github/enterprise server< 3.22.2

How to fix CVE-2026-103620

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-103620. EPSS is 0.50%. Act only if a listed version of enterprise server is installed.

Which versions are affected?

Compare what you have installed with github/enterprise server < 3.18.16; github/enterprise server < 3.19.13; github/enterprise server < 3.20.9; github/enterprise server < 3.21.7. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-862: Missing Authorization. EPSS 0.50%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 6, 2026 · NIST NVD

    Detected

    A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default branch through the GraphQL API and cause an attacker-controlled branch to become the new default. In repositories that required pull-request review but did not restrict branch deletion, this bypassed the review requirement and cause

  2. Oct 20, 2026 · NIST NVD

    Updated

    A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default branch through the GraphQL API and cause an attacker-controlled branch to become the new default. In repositories that required pull-request review but did not restrict branch deletion, this bypassed the review requirement and cause

Sources

  • CVE.orgVulnerability recordCVE-2026-103620

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-103620

    30-day exploitation probability 0.50%

    first.org
  • NIST NVDVulnerability recordCVE-2026-103620

    A missing authorization vulnerability was identified in GitHub Enterprise Server that allowed a repository collaborator with write access to delete the current default branch through the GraphQL API and cause an attacker-controlled branch to become the new default. In repositorie

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 21, 2026
  • NIST NVDOct 21, 2026