Vulnerability · Published Jul 23, 2026 · Assigned by VulnCheck

CVE-2026-65903DOMPurify before 3.4.0 ADD_TAGS Function Bypasses FORBID_TAGS

Medium 6.1

In plain English

A medium-severity security flaw in DOMPurify from cure53. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.1Medium

Exploit odds (30 days)0.3%top 74.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

DOMPurify before 3.4.0 contains a logic error in the ADD_TAGS function where short-circuit evaluation allows forbidden tags to bypass FORBID_TAGS restrictions. Attackers can craft input containing tags listed in FORBID_TAGS that are also added via ADD_TAGS function, causing them to be retained in sanitized output.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	node-dompurify	no fix listed	DEBIAN-CVE-2026-65903
Debian:13	node-dompurify	no fix listed	DEBIAN-CVE-2026-65903
Debian:14	node-dompurify	3.4.1+dfsg-1	DEBIAN-CVE-2026-65903
Ubuntu:22.04:LTS	node-dompurify	no fix listed	UBUNTU-CVE-2026-65903
Ubuntu:24.04:LTS	node-dompurify	no fix listed	UBUNTU-CVE-2026-65903
Ubuntu:26.04:LTS	node-dompurify	no fix listed	UBUNTU-CVE-2026-65903
npm	dompurify	3.4.0	GHSA-39q2-94rc-95cp

Affected products (as reported)

Vendor	Product	Versions
cure53	DOMPurify	0 – before 3.4.0

Weakness: CWE-697 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

GitHub Security Advisory (GHSA-39q2-94rc-95cp) vendor-advisory
VulnCheck Advisory: DOMPurify before 3.4.0 ADD_TAGS Function Bypasses FORBID_TAGS third-party-advisory