🛡️ CVE-2026-49216 — ux

🟡 CVSS 5.4 — Medium ✅ No Known Exploit CWE-79 NVD
5.4
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

symfony/ux-autocomplete: XSS via unescaped AJAX response data ### 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 (`
${item[labelField]}
`) 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 this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2026-49216 is classified as CWE-79: Cross-site Scripting (XSS). User-supplied data is written into a page without escaping, so attacker script runs in the browser of anyone who views it.

Affected software

CVE-2026-49216 is recorded against 2 packages.

  • symfony/ux-autocomplete (from 3.0.0 up to 3.1.0)
  • ux

Timeline and source

Published on 19 June 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com (Web)
github.com (Web)
github.com (Web)
github.com (Package)

Details

Severity Medium
CVSS Score 5.4
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CWE CWE-79
Public Exploit ✅ No
Source NVD
Published 2026-06-19
Updated 2026-08-12
Modified 2026-06-19

Affected Packages

Software From version Fixed in
symfony/ux-autocomplete 3.0.0 3.1.0
ux

Similar Threats

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