CVE-2026-49978

DOMPurify IN_PLACE Sanitization Bypass via Attached Shadow Root Inside <template>.content

Published Jul 14, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-rp9w-3fw7-7cwq DOMPurify IN_PLACE Sanitization Bypass via Attached Shadow Root Inside <template>.content
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Cure53
Cure53 dompurify
Vendors & Products Cure53
Cure53 dompurify
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N'}

threat_severity

Important

Type Values Removed Values Added
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.
Title DOMPurify IN_PLACE Sanitization Bypass via Attached Shadow Root Inside <template>.content
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 21, 2026, 2:59 PM
Reserved
Jun 2, 2026, 6:30 PM
Status
Analyzed
Published
Jul 14, 2026, 9:17 PM
Modified
Oct 24, 2026, 9:10 PM
Severity
Important
Public date
Jul 14, 2026, 8:02 PM