CVE-2026-49459 DOMPurify: IN_PLACE mode preserves attributes of a clobbered root element, allowing XSS via attacker-controlled root DOM
Attacker-controlled root DOM elements can retain event-handler attributes in IN_PLACE mode, enabling cross-site scripting attacks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-49459?
CVE-2026-49459 is a medium-severity cross-site scripting vulnerability in cure53 DOMPurify, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(root, { IN_PLACE: true }) could preserve event-handler attributes on an attacker-controlled <form> root when a descendant name clobbered properties checked by _isClobbered, because _forceRemove no-opped on the parent-less root and _sanitizeAttributes returned early. This issue is fixed in version 3.4.6.
Which versions are affected by CVE-2026-49459?
2 open source packages ship an affected version, including dompurify. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
dompurify npm | All versions | 3.4.6 |
dompurify npm | All versions | 3.4.6 |
Products include Cure53 Dompurify.
How do I fix CVE-2026-49459?
Upgrade dompurify to 3.4.6 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-49459 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-49459 exists.
Other vulnerabilities in cure53 DOMPurify
- CVE-2024-47875 DOMPurify nesting-based mXSS
- CVE-2024-48910 DOMPurify vulnerable to tampering by prototype polution
- CVE-2026-47423 DOMPurify XSS via `selectedcontent` re-clone
- CVE-2024-45801 Tampering by prototype polution in DOMPurify
- CVE-2026-49978 DOMPurify IN_PLACE Sanitization Bypass via Attached Shadow Root Inside <template>.content
Sources
Also known as DEBIAN-CVE-2026-49459, ECHO-e2af-3989-64e5, GHSA-r47g-fvhr-h676, MINI-594v-6x42-634f, MINI-5w8j-rhrr-6rm9, MINI-63fp-8prg-x3g2 and 16 more.