CVE-2026-124493JiHong88 suneditor

SunEditor before 3.4.0 Stored XSS via DocumentType Header textContent

Not on CISA's list of exploited flaws, and not in the news we track.

Chance of exploitation in 30 daysEPSS

0.34%

0%Higher than 28% of all CVEs

Exploited in the wild: Not confirmedBy CISA
Severity: 9.3 of 10Critical, CVSS
Used in ransomware: Not known
US federal deadline: None set

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About this flaw

SunEditor before 3.4.0 contains a stored cross-site scripting vulnerability in the DocumentType constructor that injects header textContent into innerHTML without HTML escaping. Attackers can store entity-encoded HTML in h1-h6 headers that executes JavaScript when editors using document:header mode initialize, enabling session cookie theft.

Published: 8 Nov 2026
Weakness: CWE-79

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