DOMPurify: Cross-realm IN_PLACE sanitization leaves executable markup intact via realm-bound `instanceof` checks

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(node, { IN_PLACE: true }) accepted same-origin foreign-realm DOM nodes while follow-on checks used parent-realm constructors, causing instanceof checks for forms, named node maps, document fragments, and elements to fail and skip clobber, template-content, and shadow-DOM sanitization branches so executable markup could survive. This issue is fixed in version 3.4.6.

DOMPurify: IN_PLACE mode preserves attributes of a clobbered root element, allowing XSS via attacker-controlled root DOM

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(root, { IN_PLACE: true }) could preserve event-handler attributes on an attacker-controlled <form> root when a descendant name clobbered properties checked by _isClobbered, because _forceRemove no-opped on the parent-less root and _sanitizeAttributes returned early. This issue is fixed in version 3.4.6.

DOMPurify: FORBID_TAGS bypassed by function-based ADD_TAGS predicate (asymmetry with FORBID_ATTR fix)

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions prior to 3.4.0 have an inconsistency between FORBID_TAGS and FORBID_ATTR handling when function-based ADD_TAGS is used. Commit c361baa added an early exit for FORBID_ATTR at line 1214. The same fix was not applied to FORBID_TAGS. At line 1118-1123, when EXTRA_ELEMENT_HANDLING.tagCheck returns true, the short-circuit evaluation skips the FORBID_TAGS check entirely. This allows forbidden elements to survive sanitization with their attributes intact. Version 3.4.0 patches the issue.

DOMPurify: Prototype Pollution to XSS Bypass via CUSTOM_ELEMENT_HANDLING Fallback

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Versions 3.0.1 through 3.3.3 are vulnerable to a prototype pollution-based XSS bypass. When an application uses `DOMPurify.sanitize()` with the default configuration (no `CUSTOM_ELEMENT_HANDLING` option), a prior prototype pollution gadget can inject permissive `tagNameCheck` and `attributeNameCheck` regex values into `Object.prototype`, causing DOMPurify to allow arbitrary custom elements with arbitrary attributes — including event handlers — through sanitization. Version 3.4.0 fixes the issue.

DOMPurify has a SAFE_FOR_TEMPLATES bypass in RETURN_DOM mode

DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Starting in version 1.0.10 and prior to version 3.4.0, `SAFE_FOR_TEMPLATES` strips `{{...}}` expressions from untrusted HTML. This works in string mode but not with `RETURN_DOM` or `RETURN_DOM_FRAGMENT`, allowing XSS via template-evaluating frameworks like Vue 2. Version 3.4.0 patches the issue.

DOMPurify XSS via Missing Rawtext Elements in SAFE_FOR_XML

DOMPurify 3.1.3 through 3.3.1 and 2.5.3 through 2.5.8, fixed in commit 2726c74, contain a cross-site scripting vulnerability that allows attackers to bypass attribute sanitization by exploiting five missing rawtext elements (noscript, xmp, noembed, noframes, iframe) in the SAFE_FOR_XML regex. Attackers can include payloads like </noscript><img src=x onerror=alert(1)> in attribute values to execute JavaScript when sanitized output is placed inside these unprotected rawtext contexts.

DOMPurify: DOMPurify Path Traversal Vulnerability

In DOMPurify through 3.2.5 before 6bc6d60, scripts/server.js does not ensure that a pathname is located under the current working directory. NOTE: the Supplier disputes the significance of this report because the "Uncontrolled data used in path expression" occurs "in a development helper script which starts a local web server if needed and must be manually started."

DOMPurify XSS via Textarea Rawtext Bypass in SAFE_FOR_XML

DOMPurify 3.1.3 through 3.2.6 and 2.5.3 through 2.5.8 contain a cross-site scripting vulnerability that allows attackers to bypass attribute sanitization by exploiting missing textarea rawtext element validation in the SAFE_FOR_XML regex. Attackers can include closing rawtext tags like </textarea> in attribute values to break out of rawtext contexts and execute JavaScript when sanitized output is placed inside rawtext elements. The 3.x branch was fixed in 3.2.7; the 2.x branch was never patched.

DOMPurify vulnerable to tampering by prototype polution

DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMPurify was vulnerable to prototype pollution. This vulnerability is fixed in 2.4.2.

DOMPurify nesting-based mXSS

DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to nesting-based mXSS. This vulnerability is fixed in 2.5.0 and 3.1.3.

dompurify: Mutation XSS in DOMPurify Due to Improper Template Literal Handling

DOMPurify before 3.2.4 has an incorrect template literal regular expression, sometimes leading to mutation cross-site scripting (mXSS).

Tampering by prototype polution in DOMPurify

DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. It has been discovered that malicious HTML using special nesting techniques can bypass the depth checking added to DOMPurify in recent releases. It was also possible to use Prototype Pollution to weaken the depth check. This renders dompurify unable to avoid cross site scripting (XSS) attacks. This issue has been addressed in versions 2.5.4 and 3.1.3 of DOMPurify. All users are advised to upgrade. There are no known workarounds for this vulnerability.

Cure53 DOMPurify before 2.0.17 allows mutation XSS. This occurs because a serialize-parse roundtrip does not necessarily return the original DOM tree, and a namespace can change from HTML to MathML, as demonstrated by nesting of FORM elements.

DOMPurify before 1.0.11 allows reverse tabnabbing in demos/hooks-target-blank-demo.html because links lack a 'rel="noopener noreferrer"' attribute.

DOMPurify before 2.0.1 allows XSS because of innerHTML mutation XSS (mXSS) for an SVG element or a MATH element, as demonstrated by Chrome and Safari.