Cure53 DOMPurify up to 3.3.3 DOMPurify.sanitize cross site scripting

Summaryinfo

A vulnerability was found in Cure53 DOMPurify up to 3.3.3 and classified as problematic. Impacted is the function DOMPurify.sanitize. The manipulation results in cross site scripting. This vulnerability is identified as CVE-2026-65911. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Cure53 DOMPurify up to 3.3.3. It has been classified as problematic. Affected is the function DOMPurify.sanitize. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-65911 since 07/23/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 3.4.0 eliminates this vulnerability.

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Productinfo

Vendor

• Cure53

Name

• DOMPurify

Version

• 3.3.0
• 3.3.1
• 3.3.2
• 3.3.3

Website

• Product: https://github.com/cure53/DOMPurify/

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