CVE-2026-2266: Improper neutralization of input vulnerability was identified in GitHub Enterprise Server that allowed cross-site scripting via task list content and enabled arbitrary HTML injection
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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-2266?
CVE-2026-2266 is rated as a medium severity vulnerability due to its potential for cross-site scripting attacks.
How do I fix CVE-2026-2266?
To fix CVE-2026-2266, upgrade your GitHub Enterprise Server to version 3.20 or later.
What does CVE-2026-2266 exploit?
CVE-2026-2266 exploits improper neutralization of input, allowing for cross-site scripting via task list content.
Who is affected by CVE-2026-2266?
CVE-2026-2266 affects users of GitHub Enterprise Server versions prior to 3.20.
What are the implications of CVE-2026-2266?
The implications of CVE-2026-2266 include the potential for attackers to inject arbitrary HTML and execute malicious scripts in the context of the victim's browser.