GHSA-mwqm-4fw3-cjvr
GHSA-mwqm-4fw3-cjvr is a Cross-site Scripting (XSS) vulnerability in symfony/ux-autocomplete. O3 Security confirms whether GHSA-mwqm-4fw3-cjvr is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
symfony/ux-autocomplete: XSS via unescaped AJAX response data
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
symfony/ux-autocomplete🐘symfony/ux-autocompleteReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
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 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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | symfony/ux-autocomplete | ≥ 2.2.0&&< 2.36.0 | 2.36.0 |
| 🐘Packagist | symfony/ux-autocomplete | ≥ 3.0.0&&< 3.1.0 | 3.1.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/ux-autocomplete. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update symfony/ux-autocomplete to 2.36.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mwqm-4fw3-cjvr is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-mwqm-4fw3-cjvr is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-mwqm-4fw3-cjvr. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-mwqm-4fw3-cjvr in your dependencies?
O3 detects GHSA-mwqm-4fw3-cjvr across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.