Vulnerability · Published Jul 23, 2026 · Assigned by VulnCheck
CVE-2026-65911DOMPurify before 3.4.0 XSS via ADD_ATTR/ADD_TAGS State Leakage
Medium 6.1
In plain English
A medium-severity cross-site scripting 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 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
In DOMPurify through 3.3.3, function predicates supplied via ADD_ATTR or ADD_TAGS to DOMPurify.sanitize() persist in internal state (EXTRA_ELEMENT_HANDLING) across subsequent sanitize() calls on the same instance. If a later call on the same instance provides ADD_ATTR or ADD_TAGS as an array rather than a function, the previously set function handler is neither cleared nor overwritten, so it continues to approve attacker-controlled attributes or tags. This can allow dangerous event-handler attributes or forbidden tags (bypassing FORBID_TAGS) to survive sanitization, resulting in cross-site scripting. The vendor (Cure53) considers this an edge case outside DOMPurify's threat model; the referenced advisory lists 3.4.0 as the patched version.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-dompurify | no fix listed | DEBIAN-CVE-2026-65911 |
| Debian:13 | node-dompurify | no fix listed | DEBIAN-CVE-2026-65911 |
| Debian:14 | node-dompurify | 3.4.1+dfsg-1 | DEBIAN-CVE-2026-65911 |
| Ubuntu:22.04:LTS | node-dompurify | no fix listed | UBUNTU-CVE-2026-65911 |
| Ubuntu:24.04:LTS | node-dompurify | no fix listed | UBUNTU-CVE-2026-65911 |
| Ubuntu:26.04:LTS | node-dompurify | no fix listed | UBUNTU-CVE-2026-65911 |
Affected products (as reported)
Weakness: CWE-79 · 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-9p3w-6h5p-cv75) vendor-advisory
- VulnCheck Advisory: DOMPurify before 3.4.0 XSS via ADD_ATTR/ADD_TAGS State Leakage third-party-advisory