Medium severity · published Jul 14, 2026
CVE-2026-49978
DOMPurify IN_PLACE Sanitization Bypass via Attached Shadow Root Inside <template>.content
6.1
CVSS
0.4%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 35% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DO
DOMPurify · cure53
< 3.4.6 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-49978
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-49978
Patch
https://github.com/cure53/DOMPurify/commit/ca30f070c360df162a3e3848e80e6fd3c9e74bff
Release Notes
https://github.com/cure53/DOMPurify/releases/tag/3.4.7
Vendor Advisory
https://github.com/cure53/DOMPurify/security/advisories/GHSA-rp9w-3fw7-7cwq
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