CVE-2026-49216
symfony/ux-autocomplete: XSS via unescaped AJAX response data
Description
### Description The Stimulus controller shipped with `symfony/ux-autocomplete` renders AJAX response items into the dropdown by interpolating the `text` field directly into HTML template literals (`<div>${item[labelField]}</div>`) inside `_createAutocompleteWithRemoteData()`. The value is parsed as HTML rather than text, so any markup contained in the AJAX response is executed by the browser. When the dropdown values are derived from user-supplied content, an attacker can craft a string that triggers stored XSS in the browser of any other user who later opens a page containing an autocomplete widget backed by the same data. ### Resolution The `option` and `item` renderers used in `_createAutocompleteWithRemoteData()` now use TomSelect's `escape` helper to HTML-escape the value by default. Endpoints that legitimately return HTML (for example, to highlight the search term) can opt back in to the previous behavior by setting `options_as_html: true`. The `AutocompleteChoiceTypeExtension` normalizer that previously forced `options_as_html=false` when `autocomplete_url` was set has been dropped so the opt-in is reachable from the form layer. The patch for this issue is available [here](https://github.com/symfony/ux/commit/842ae54bc74de389299f975f01aafae272cb0019) for branch 2.x (and forward-ported to 3.x). ### Credits Symfony would like to thank Alex Ashkov for reporting the issue and Hugo Alliaume for providing the fix.
How to fix CVE-2026-49216
To remediate CVE-2026-49216, upgrade the affected package to a fixed version below.
- —upgrade to 2.36.0 or later
Is CVE-2026-49216 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-49216.
Affected packages (1)
- >= 2.2.0, < 2.36.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N |