PT-2026-51122 · Packagist · Symfony/Ux-Icons

Publicado

2026-06-19

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Atualizado

2026-06-19

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CVE-2026-55877

CVSS v3.1

6.1

Média

VetorAV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Description

The ux icon() Twig function is marked is safe=['html'], so Twig never escapes its output. Icon::toHtml() inlines the SVG source verbatim into the page. Browsers execute <script> elements and on* event-handler attributes found inside inline SVG, making any unsanitized icon a vector for cross-site scripting.
Two code paths were affected. In the local file path, Icon::fromFile() only stripped <script> elements that were direct children of <svg>, leaving nested scripts and all on* attributes untouched despite a code comment claiming broader protection. In the Iconify on-demand path (enabled by default), the remote JSON body field was wrapped into an Icon object with no sanitization at all. Concrete attack vectors include a malicious SVG icon pack from a third-party theme or downloaded icon set, or a controlled Iconify endpoint configured via iconify.endpoint (including a poisoned cache).

Resolution

Introducing an IconFactory that centralizes sanitization across every icon source before an Icon object is created. The sanitizer removes script-capable elements (script, foreignObject, iframe, object, embed), SMIL animations targeting on*, href, or xlink:href attributes, CDATA sections, processing instructions, all on* attributes, and javascript:, vbscript:, and data:text/html URL schemes. <style> elements are kept for theming but have any handlers stripped. Icons that contain none of these constructs are byte-for-byte identical after sanitization.

Credits

Symfony would like to thank Pascal Cescon for reporting the issue and Hugo Alliaume for providing the fix.

Exploit

Correção

XSS

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Enumeração de Fraquezas

Identificadores relacionados

CVE-2026-55877
GHSA-6V8J-33HC-MV84

Produtos afetados

Symfony/Ux-Icons