Is CVE-2026-2266 in the CISA KEV catalog?

No. CVE-2026-2266 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-2266?

CVE-2026-2266 has a CVSS v3 base score of 5.4 (MEDIUM).

What is the EPSS score for CVE-2026-2266?

CVE-2026-2266 has an EPSS score of 0.18% (7th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-2266?

Upgrade enterprise server to 3.19.3 or later.

CVE & CISA-KEV Catalog

CVE-2026-2266

MEDIUM

5.4

CVSS v3

NVD

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.

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

enterprise serverNVD

Affected:>= 3.19.0, < 3.19.3Fixed in:3.19.3CVE-2026-2266derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Exploit Intelligence

0.18%probability of exploitation in 30 days

7thpercentile

Low risk: more likely to be exploited than 7% of all known CVEs.

References

Release Notes2

Related Vulnerabilities

Other CWE-79 (Cross-Site Scripting (XSS)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-11022	Medium	6.9	99%	-	Fix
CVE-2019-3929	Critical	9.8	99%	KEV	Fix
CVE-2020-9496	Medium	6.1	99%	-	-
CVE-2023-28341	Medium	6.1	99%	-	Fix
CVE-2018-12998	Medium	6.1	98%	-	-
CVE-2025-4123	High	7.6	98%	-	Fix

Embed a live status badge for CVE-2026-2266

Markdown

[![CVE-2026-2266](https://tridentstack.com/cve/badge/CVE-2026-2266.svg)](https://tridentstack.com/cve/CVE-2026-2266)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-2266"><img src="https://tridentstack.com/cve/badge/CVE-2026-2266.svg" alt="CVE-2026-2266"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-12.