How severe is CVE-2026-49216?

No CVSS score has been assigned to CVE-2026-49216 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-49216?

CVE-2026-49216 affects the following packages: symfony/ux-autocomplete (Packagist), symfony/ux-autocomplete (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-49216?

Update symfony/ux-autocomplete to 2.36.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-49216 is resolved across your whole dependency graph.

How do I detect CVE-2026-49216 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/ux-autocomplete, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-49216 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-49216 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-49216 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-49216?

CVE-2026-49216 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 24th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-49216?

CVE-2026-49216 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-49216 published, and has it been updated?

CVE-2026-49216 was published on July 17, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-49216 — ux-autocomplete

Fix: symfony/ux@842ae54

CVE-2026-49216 is a Cross-site Scripting (XSS) vulnerability in symfony/ux-autocomplete. A fix is available for symfony/ux-autocomplete — see the affected versions and patch details below.

Symfony UX: XSS in symfony/ux-autocomplete via unescaped AJAX response data

Also known asGHSA-mwqm-4fw3-cjvr

Published

Jul 17, 2026

Updated

Oct 21, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 25, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-49216.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs24th percentile — riskier than 24% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

🐘symfony/ux-autocomplete🐘symfony/ux-autocomplete

Real-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

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

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`symfony/ux-autocomplete`	≥ 2.2.0&&< 2.36.0	2.36.0`composer require symfony/ux-autocomplete:^2.36.0`
🐘Packagist	`symfony/ux-autocomplete`	≥ 3.0.0&&< 3.1.0	3.1.0`composer require symfony/ux-autocomplete:^3.1.0`

Affected Products

1 product · 2 configurations

Application

uxsymfony

≥ 2.2.0 && < 2.36.0

1 version

3.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symfony/ux-autocomplete, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 CVE-2026-49216 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

### 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 autocomplet

O3 Security · Impact-Aware SCA

Is CVE-2026-49216 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVE-2026-49216 — ux-autocomplete

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

Real-World Exposure

Description

Description

Resolution

Credits

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2026-49216 in your dependencies?