Symfony UX up to 2.35.x/3.0.x Autocomplete _createAutocompleteWithRemoteData dropdown cross site scripting

Summaryinfo

A vulnerability classified as problematic has been found in Symfony UX up to 2.35.x/3.0.x. This impacts the function _createAutocompleteWithRemoteData of the component Autocomplete. This manipulation of the argument dropdown causes cross site scripting. This vulnerability is handled as CVE-2026-49216. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Symfony UX up to 2.35.x/3.0.x. It has been declared as problematic. Affected by this vulnerability is the function _createAutocompleteWithRemoteData of the component Autocomplete. The manipulation of the argument dropdown with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. The summary by CVE is:

Symfony UX is a JavaScript ecosystem for Symfony. From 2.2.0 until 2.36.0 and 3.1.0, the Stimulus controller in symfony/ux-autocomplete renders AJAX response items in _createAutocompleteWithRemoteData() by interpolating the text field into HTML template literals (<div>${item[labelField]}</div>) rather than text, allowing attacker-controlled markup from user-supplied dropdown values to execute in the browser of any user who opens an autocomplete widget backed by the same data. This issue is fixed in versions 2.36.0 and 3.1.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-49216 since 05/28/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 2.36.0 or 3.1.0 eliminates this vulnerability.

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Productinfo

Vendor

• Symfony

Name

• UX

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 3.0

License

• open-source

Website

• Product: https://github.com/symfony/ux/

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