---
id: CVE-2026-49216
title: 'symfony/ux-autocomplete: XSS via unescaped AJAX response data'
summary: 'symfony/ux-autocomplete: XSS via unescaped AJAX response data'
severity: medium
cwe:
  - CWE-79
vendor: symfony
product: symfony/ux-autocomplete
affected:
  - 'symfony/ux-autocomplete >= 2.2.0, < 2.36.0'
  - 'symfony/ux-autocomplete >= 3.0.0, < 3.1.0'
patched:
  - symfony/ux-autocomplete 2.36.0
  - symfony/ux-autocomplete 3.1.0
published: '2026-06-19'
updated: '2026-06-19'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-mwqm-4fw3-cjvr'
references:
  - url: 'https://github.com/symfony/ux/security/advisories/GHSA-mwqm-4fw3-cjvr'
  - url: >-
      https://github.com/symfony/ux/commit/842ae54bc74de389299f975f01aafae272cb0019
  - url: >-
      https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/ux-autocomplete/CVE-2026-49216.yaml
  - url: 'https://github.com/advisories/GHSA-mwqm-4fw3-cjvr'
tags:
  - ghsa
  - composer
ingestedAt: '2026-06-22T15:52:21.061Z'
ecosystem: composer
epss: 0.00312
epssPercentile: 0.21355
---

## Overview

### 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.

## Affected packages

- `symfony/ux-autocomplete >= 2.2.0, < 2.36.0`
- `symfony/ux-autocomplete >= 3.0.0, < 3.1.0`

## Remediation

Upgrade to a patched release:

- `symfony/ux-autocomplete 2.36.0`
- `symfony/ux-autocomplete 3.1.0`