CVE-2026-65911
MediumCVSS 6.1Exploitation Probability (EPSS)
Low risk8th percentile - higher than 8% of all known CVEs
Summary
In DOMPurify through version 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 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.
Risk Assessment
The risk involves potential script execution in the victim's browser, which could lead to data theft, account takeover, or other malicious actions.
Recommendation
It is recommended to upgrade DOMPurify to version 3.4.0 or later, which contains the fix.
Other vulnerabilities in DOMPurify
See all- CVE-2026-75838Medium
DOMPurify before 3.4.13 contains a cross-site scripting vulnerability in IN_PLACE sanitization where element-removal hooks fail to neutralize detached subtrees. Attackers can supply HTML with event handlers on descendant elements that execute after sanitization completes, even though the returned root appears clean.
- CVE-2026-66010Medium
DOMPurify before version 3.4.12 fails to execute the afterSanitizeElements hook for custom elements allowed via CUSTOM_ELEMENT_HANDLING.tagNameCheck, allowing attributes to bypass application security policies. Attackers can preserve sensitive attributes on custom elements that later re-inject them into innerHTML sinks, creating second-order XSS gadgets.
- CVE-2026-65914Medium
DOMPurify before version 3.3.2 has a mutation-XSS vulnerability when sanitized HTML is reinserted into special parsing contexts using innerHTML with wrappers like script, xmp, iframe, noembed, noframes, or noscript. Attackers can craft payloads with closing sequences that break out of the wrapper context during reparsing, reactivating dangerous markup with event handlers to execute JavaScript.
- CVE-2026-65913Medium
DOMPurify before version 3.3.2 contains a prototype pollution vulnerability in USE_PROFILES mode. Attackers can set Array.prototype properties like onclick to true, causing DOMPurify to accept event handlers as allowed attributes, leading to DOM-based XSS.
- CVE-2026-65912Medium
DOMPurify before version 3.3.2 contains a URI validation bypass vulnerability when ADD_ATTR is provided as a predicate function via EXTRA_ELEMENT_HANDLING.attributeCheck. Attackers can supply a predicate that accepts specific attribute and tag combinations to bypass URI-safe validation, allowing unsafe protocols like javascript: to survive sanitization, leading to DOM-based XSS when the link is activated.
- CVE-2026-65904Medium
DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function returns false for foreign-realm nodes, causing DOMPurify to stringify the element (yielding '[object HTMLDivElement]'), silently reset IN_PLACE to false, and return the unsanitized element unchanged with any XSS payloads intact.
- CVE-2026-65903Medium
DOMPurify before version 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.
- CVE-2026-65902Medium
DOMPurify before version 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.
- CVE-2026-65901Medium
DOMPurify through version 3.4.6 contains a cross-site scripting vulnerability in IN_PLACE mode that trusts attacker-controlled nodeName on live non-form nodes. Attackers can supply hostile live DOM objects with real script children whose observable nodeName is clobbered to appear as allowed elements, causing scripts to execute when the sanitized tree is inserted into a live document.
- CVE-2026-65900Medium
DOMPurify versions 3.0.0 to before 3.4.8, when configured with SAFE_FOR_TEMPLATES and a DOM output mode, fail to strip template expressions inside <template> elements. The final scrub pass does not process template.content, so expressions may survive and be evaluated by a downstream template engine.
Original NVD description (English source)
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.