CVE-2026-2266 Details
Description
An improper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed DOM-based cross-site scripting via task list content. The task list content extraction logic did not properly re-encode browser-decoded text nodes before rendering, allowing user-supplied HTML to be injected into the page. An authenticated attacker could craft malicious task list items in issues or pull requests to execute arbitrary scripts in the context of another user's browser session. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.20 and was fixed in versions 3.18.6 and 3.19.3. This vulnerability was reported via the GitHub Bug Bounty program.
A DOM-based cross-site scripting vulnerability has been identified in GitHub Enterprise Server. This issue arises from improper handling of task list content, which allowed user-supplied HTML to be injected and executed as scripts in the context of another user's browser session. The vulnerability affects all versions of GitHub Enterprise Server prior to 3.20. An authenticated attacker could exploit this by crafting malicious task list items in issues or pull requests.
Users can upgrade to GitHub Enterprise Server versions 3.18.6 or 3.19.3, both of which include the necessary fix.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Mar 11, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://docs.github.com/en/[email protected]/admin/release-notes#3.18.6 | [email protected] | Release Notes |
| https://docs.github.com/en/[email protected]/admin/release-notes#3.19.3 | [email protected] | Release Notes |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-79 | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| github enterprise server | < 3.18.6 >= 3.19.0, < 3.19.3 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Mar 12, 2026 | Initial Analysis | [email protected] |
| Mar 10, 2026 | New CVE Received | [email protected] |