CVE-2026-65902: DOMPurify before 3.4.7 (affected versions <= 3.4.5) passes direct references to the module-level DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement and u

mediumCVSS 6.1CVE-2026-65902

DOMPurify before 3.4.7 (affected versions <= 3.4.5) passes direct references to the module-level DEFAULT_ALLOWED_TAGS and DEFAULT_ALLOWED_ATTR sets to the uponSanitizeElement and uponSanitizeAttribute hooks via data.allowedTags / data.allowedAttributes when sanitize is called without an explicit cfg.ALLOWED_TAGS / cfg.ALLOWED_ATTR array. A hook that mutates these fields permanently widens the default allow-lists for the lifetime of the DOMPurify instance, so all subsequent default-config sanitize calls inherit the widened defaults and attacker payloads using the poisoned tag/attribute name survive sanitization. removeAllHooks(), clearConfig(), and passing a fresh cfg do not recover the state; only constructing a new DOMPurify instance does.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: medium — CVSS 6.1
Published: 2026-07-23
Last updated: 2026-07-28
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-65902

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-2026-659020.21% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 11% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-65902	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

mediumGHSA-76mc-f452-cxcm: DOMPurify: Hook mutation of `data.allowedTags` / `data.allowedAttributes` permanently pol…ghsa

Recent advisories for DOMPurify

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.

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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