CVE-2026-41673

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. In @xmldom/xmldom prior to versions 0.9.10 and 0.8.13 and xmldom version 0.6.0 and prior, seven recursive traversals in lib/dom.js operate without a depth limit. A sufficiently deeply nested DOM tree causes a RangeError: Maximum call stack size exceeded, crashing the application. This issue has been patched in versions @xmldom/xmldom versions 0.9.10 and 0.8.13.

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. In @xmldom/xmldom prior to versions 0.9.10 and 0.8.13 and xmldom version 0.6.0 and prior, seven recursive traversals in lib/dom.js operate without a depth limit. A sufficiently deeply nested DOM tree causes a RangeError: Maximum call stack size exceeded, crashing the application. This issue has been patched in versions @xmldom/xmldom versions 0.9.10 and 0.8.13.

Summary

Seven recursive traversals in lib/dom.js operate without a depth limit. A sufficiently deeply nested DOM tree causes a RangeError: Maximum call stack size exceeded, crashing the application.

Reported operations:

• Node.prototype.normalize() — reported by @praveen-kv (email 2026-04-05) and @KarimTantawey (GHSA-fwmp-8wwc-qhv6, via DOMParser.parseFromString())
• XMLSerializer.serializeToString() — reported by @Jvr2022 (GHSA-2v35-w6hq-6mfw) and @KarimTantawey (GHSA-j2hf-fqwf-rrjf)

Additionally, discovered in research:

• Element.getElementsByTagName() / getElementsByTagNameNS() / getElementsByClassName() / getElementById()
• Node.cloneNode(true)
• Document.importNode(node, true)
• node.textContent (getter)
• Node.isEqualNode(other)

All seven share the same root cause: pure-JavaScript recursive tree traversal with no depth guard. A single deeply nested document (parsed successfully) triggers any or all of these operations.

Details

Root cause

lib/dom.js implements DOM tree traversals as depth-first recursive functions. Each level of element nesting adds one JavaScript call frame. The JS engine's call stack is finite; once exhausted, a RangeError: Maximum call stack size exceeded is thrown. This error may not be caught reliably at stack-exhaustion depths because the catch handler itself requires stack frames to execute — especially in async scenarios, where an uncaught RangeError inside a callback or promise chain can crash the entire Node.js process.

Parsing a deeply nested document succeeds — the SAX parser in lib/sax.js is iterative. The crash occurs during subsequent operations on the parsed DOM.

Node.prototype.normalize() — reported by @praveen-kv

lib/dom.js:1296–1308 (main):

normalize: function () {
    var child = this.firstChild;
    while (child) {
        var next = child.nextSibling;
        if (next && next.nodeType == TEXT_NODE && child.nodeType == TEXT_NODE) {
            this.removeChild(next);
            child.appendData(next.data);
        } else {
            child.normalize();   // recursive call — no depth guard
            child = next;
        }
    }
},

Crash threshold (Node.js 18, default stack): ~10,000 levels.

XMLSerializer.serializeToString() — reported by @Jvr2022

lib/dom.js:2790–2974 (main): The internal serializeToString worker recurses into child nodes at four call sites, each passing a visibleNamespaces.slice() copy. The per-frame allocation causes earlier stack exhaustion than normalize().

Crash threshold (Node.js 18, default stack): ~5,000 levels.

Additional recursive entry points

All five crash at ~10,000 levels on Node.js 18.

| Function | Definition | Public API entry point(s) | Crash depth (Node.js 18) | |-----------------------------|----------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------|--------------------------| | _visitNode | lib/dom.js:1529 | getElementsByTagName(), getElementsByTagNameNS(), getElementsByClassName(), getElementById() | ~10,000 levels | | cloneNode (module fn) | lib/dom.js:3037 | Node.prototype.cloneNode(true) …

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. In @xmldom/xmldom prior to versions 0.9.10 and 0.8.13 and xmldom version 0.6.0 and prior, seven recursive traversals in lib/dom.js operate without a depth limit. A sufficiently deeply nested DOM tree causes a RangeError: Maximum call stack size exceeded, crashing the application. This issue has been patched in versions @xmldom/xmldom versions 0.9.10 and 0.8.13.

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. In @xmldom/xmldom prior to versions 0.9.10 and 0.8.13 and xmldom version 0.6.0 and prior, seven recursive traversals in lib/dom.js operate without a depth limit. A sufficiently deeply nested DOM tree causes a RangeError: Maximum call stack size exceeded, crashing the application. This issue has been patched in versions @xmldom/xmldom versions 0.9.10 and 0.8.13.

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. In @xmldom/xmldom prior to versions 0.9.10 and 0.8.13 and xmldom version 0.6.0 and prior, seven recursive traversals in lib/dom.js operate without a depth limit. A sufficiently deeply nested DOM tree causes a RangeError: Maximum call stack size exceeded, crashing the application. This issue has been patched in versions @xmldom/xmldom versions 0.9.10 and 0.8.13.