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Fencer Vulns
medium 5.4

CVE-2026-49216 json

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

published 2026-06-19 4 mo ago modified 2026-10-24 15 d ago also GHSA-mwqm-4fw3-cjvr , EUVD-2026-45216

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist symfony/ux-autocomplete 2.36.0, 3.1.0
  • symfony ux 2.36.0

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist symfony/ux-autocomplete
>=2.2.0, <2.36.0
>=3.0.0, <3.1.0
2.36.0
3.1.0

Affected products

  • symfony ux

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.