DOM-Based Cross-Site Scripting in GitHub Enterprise Server
CVE-2026-2266

7.4HIGH

Key Information:

Vendor

Github
Status
Enterprise Server
Vendor
CVE Published:
10 March 2026

What is CVE-2026-2266?

A vulnerability exists in GitHub Enterprise Server enabling DOM-based cross-site scripting due to improper handling of user input in task list content. By exploiting this flaw, authenticated attackers could create malicious task items in issues or pull requests, allowing arbitrary scripts to execute within another user's browser session. This issue affects all versions prior to 3.20 and has been addressed in updates 3.18.6 and 3.19.3, as reported through the GitHub Bug Bounty program.

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Deploy the Patch

Affected Version(s)

Enterprise Server 3.18.0 <= 3.18.5

Enterprise Server 3.19.0 <= 3.19.2

References

https://docs.github.com/en/enterprise-server@3.18/admin/r...
release-notes
https://docs.github.com/en/enterprise-server@3.19/admin/r...
release-notes

CVSS V4

Score:
7.4
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

André Storfjord Kristiansen
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