CVE-2026-49978 — MEDIUM (6.1)

Vulnerability Description

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.7, DOMPurify IN_PLACE sanitization could skip shadow contents attached to an element inside <template>.content, allowing attacker-controlled markup such as event handlers, JavaScript URLs, or scripts to survive and execute when an application cloned and inserted the sanitized template. This issue is fixed in version 3.4.7.

CVSS Score

6.1

MEDIUM

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality

LOW

Integrity

LOW

Availability

NONE

Affected Products

Vendor	Product	Versions
Cure53	Dompurify	< 3.4.7

Related Weaknesses (CWE)

CWE-79

References

https://github.com/cure53/DOMPurify/commit/ca30f070c360df162a3e3848e80e6fd3c9e74Patch
https://github.com/cure53/DOMPurify/releases/tag/3.4.7Release Notes
https://github.com/cure53/DOMPurify/security/advisories/GHSA-rp9w-3fw7-7cwqVendor AdvisoryExploit
https://github.com/cure53/DOMPurify/security/advisories/GHSA-rp9w-3fw7-7cwqVendor AdvisoryExploit

FAQ

What is CVE-2026-49978?

CVE-2026-49978 is a vulnerability with a CVSS score of 6.1 (MEDIUM). DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.7, DOMPurify IN_PLACE sanitization could skip shadow contents attached to an element inside <template>.co...

How severe is CVE-2026-49978?

CVE-2026-49978 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-49978?

Check the references section above for vendor advisories and patch information. Affected products include: Cure53 Dompurify.