CVE-2026-124493 PUBLISHED

SunEditor before 3.4.0 Stored XSS via DocumentType Header textContent

Assigner: VulnCheck
Reserved: 08.11.2026 Published: 08.11.2026 Updated: 08.11.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
CVSS Score: 9.3

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	High	Integrity	High
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	JiHong88
Product	suneditor
Versions	Default: unaffected affected from 0 to 3.4.0 (excl.) Version 3.4.0 is unaffected

Credits

iElloc finder

References

Problem Types

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE