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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

Published: Mar 10, 2026Updated: Mar 12, 2026 Sources: CVE List NVDCWE-79
NVD MITRE
5.4CVSSMEDIUM
EPSS Score
0.2%
Top 92.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:RS:CC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:RUser Interaction
Required
Scope
S:CScope
Changed
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-79

Affected Products

enterprise servergithubDevTools & CI
Enterprise ServerGitHubDevTools & CI
githubcommercialUSDevTools & CIaka github

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.6
docs.github.com
https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.3
docs.github.com

Timeline

Published
Mar 10, 2026
Last Updated
Mar 12, 2026

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