MapLibre GL JS is an interactive vector tile map library for web browsers. Prior to 6.4.1, DOM.sanitize() in src/util/dom.ts iterates elem.attributes as a live NamedNodeMap while removeAttributes() removes attributes from the same collection, shifting indexes and skipping an adjacent dangerous attribute. An attacker who controls untrusted third-party style attribution strings or user-supplied custom attributions can supply consecutive dangerous attributes, causing an attribute such as onload or ontoggle to survive sanitization and execute when the attribution control inserts the content into innerHTML. A victim must render the affected map content for the script to execute. This issue is fixed in version 6.4.1.

Affected: npm: maplibre-gl

### Impact `DOM.sanitize()` in `src/util/dom.ts` iterated `elem.attributes` (a live `NamedNodeMap`) while calling `elem.removeAttribute()` in the same loop. Removing an attribute shifts subsequent attributes down by one index, causing the iterator to skip the adjacent attribute.

An attacker can provide an HTML payload with consecutive dangerous attributes (such as `<details open onload="1" ontoggle="...">`). The first attribute is stripped while the second survives and executes upon insertion into `innerHTML` via the attribution control without requiring user interaction (zero-click XSS).

Applications rendering untrusted/third-party style attribution strings or user-supplied custom attributions are impacted.

### Patches The issue has been resolved by creating a static snapshot of attributes using `Array.from(elem.attributes)` before iteration. Please upgrade to `maplibre-gl` version **6.4.1** (or latest).

### Workarounds Sanitizing the attribute field of a source before passing it down to maplibre