Vulnerability · Published Jul 14, 2026 · Assigned by GitHub_M
CVE-2026-49978DOMPurify IN_PLACE Sanitization Bypass via Attached Shadow Root Inside <template>.content
Medium 6.3
In plain English
A medium-severity cross-site scripting in DOMPurify from cure53. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-dompurify | no fix listed | DEBIAN-CVE-2026-49978 |
| Debian:13 | node-dompurify | no fix listed | DEBIAN-CVE-2026-49978 |
| Debian:14 | node-dompurify | 3.4.12+dfsg-1 | DEBIAN-CVE-2026-49978 |
| Ubuntu:22.04:LTS | node-dompurify | no fix listed | UBUNTU-CVE-2026-49978 |
| Ubuntu:24.04:LTS | node-dompurify | no fix listed | UBUNTU-CVE-2026-49978 |
| Ubuntu:26.04:LTS | node-dompurify | no fix listed | UBUNTU-CVE-2026-49978 |
| Ubuntu:26.10 | node-dompurify | no fix listed | UBUNTU-CVE-2026-49978 |
| npm | dompurify | 3.4.7 | GHSA-rp9w-3fw7-7cwq |
Affected products (as reported)
Weakness: CWE-79 · 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
References
- https://github.com/cure53/DOMPurify/security/advisories/GHSA-rp9w-3fw7-7cwq x_refsource_CONFIRM
- https://github.com/cure53/DOMPurify/commit/ca30f070c360df162a3e3848e80e6fd3c9e74bff x_refsource_MISC
- https://github.com/cure53/DOMPurify/releases/tag/3.4.7 x_refsource_MISC