CVE-2026-49978: 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

mediumCVSS 6.1CVE-2026-49978

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.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: medium — CVSS 6.1
Published: 2026-07-14
Last updated: 2026-07-21
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-49978

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-499780.33% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-49978	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[NEW] [high] Red Hat Ansible Automation Platform (node-tar, linkify-it, protobufjs, brace-expansion, fast-uri,…cert-bund

Recent advisories for DOMPurify is a

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

high[NEW] [high] Red Hat Ansible Automation Platform (node-tar, linkify-it, protobufjs, brace-expansion, fast-uri,…cert-bund · 2026-07-31
mediumCVE-2026-66010: DOMPurify before 3.4.12 fails to execute afterSanitizeElements hook for custom elements allowe…nvd · 2026-07-24
mediumCVE-2026-65914: DOMPurify before 3.3.2 contains a mutation-XSS vulnerability when sanitized HTML is reinserted…nvd · 2026-07-23
mediumCVE-2026-65913: DOMPurify before 3.3.2 contains a prototype pollution vulnerability in USE_PROFILES mode that …nvd · 2026-07-23
mediumCVE-2026-65912: DOMPurify before 3.3.2 contains a URI validation bypass vulnerability when ADD_ATTR is provide…nvd · 2026-07-23
mediumCVE-2026-65911: In DOMPurify through 3.3.3, function predicates supplied via ADD_ATTR or ADD_TAGS to DOMPurify…nvd · 2026-07-23