CVE-2026-55877: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in symfony ux
Symfony UX is a JavaScript ecosystem for Symfony. From 2.17.0 before 2.36.1 and from 3.0.0 before 3.2.0, the ux_icon() Twig function is marked is_safe=['html'] and Icon::toHtml() inlines SVG source verbatim, allowing unsanitized local SVG files or Iconify on-demand JSON body responses containing nested script elements, on* event handlers, or dangerous URL schemes to execute cross-site scripting. This issue is fixed in versions 2.36.1 and 3.2.0.
AI Analysis
Technical Summary
Symfony UX versions >=2.17.0 <2.36.1 and >=3.0.0 <3.2.0 contain a cross-site scripting vulnerability due to the ux_icon() Twig function being marked as safe for HTML output and Icon::toHtml() inlining SVG content verbatim. This allows unsanitized SVG files or Iconify JSON responses with nested script elements, event handlers, or dangerous URL schemes to execute arbitrary scripts in the context of the web page. The vulnerability is addressed in versions 2.36.1 and 3.2.0.
Potential Impact
Successful exploitation can lead to limited confidentiality and integrity impact by executing arbitrary scripts in the user's browser, potentially leading to session hijacking, defacement, or other client-side attacks. There is no impact on availability. The vulnerability requires user interaction (UI:R) and can be exploited remotely without privileges (AV:N, PR:N).
Mitigation Recommendations
Upgrade affected Symfony UX versions to 2.36.1 or later, or 3.2.0 or later, where the vulnerability is fixed. No other official remediation or temporary fix is indicated. Patch status is confirmed fixed in these versions.
CVE-2026-55877: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in symfony ux
Description
Symfony UX is a JavaScript ecosystem for Symfony. From 2.17.0 before 2.36.1 and from 3.0.0 before 3.2.0, the ux_icon() Twig function is marked is_safe=['html'] and Icon::toHtml() inlines SVG source verbatim, allowing unsanitized local SVG files or Iconify on-demand JSON body responses containing nested script elements, on* event handlers, or dangerous URL schemes to execute cross-site scripting. This issue is fixed in versions 2.36.1 and 3.2.0.
CVSS v3.1
Score 6.1medium
Affected software
pkg:github/symfony/uxRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Symfony UX versions >=2.17.0 <2.36.1 and >=3.0.0 <3.2.0 contain a cross-site scripting vulnerability due to the ux_icon() Twig function being marked as safe for HTML output and Icon::toHtml() inlining SVG content verbatim. This allows unsanitized SVG files or Iconify JSON responses with nested script elements, event handlers, or dangerous URL schemes to execute arbitrary scripts in the context of the web page. The vulnerability is addressed in versions 2.36.1 and 3.2.0.
Potential Impact
Successful exploitation can lead to limited confidentiality and integrity impact by executing arbitrary scripts in the user's browser, potentially leading to session hijacking, defacement, or other client-side attacks. There is no impact on availability. The vulnerability requires user interaction (UI:R) and can be exploited remotely without privileges (AV:N, PR:N).
Mitigation Recommendations
Upgrade affected Symfony UX versions to 2.36.1 or later, or 3.2.0 or later, where the vulnerability is fixed. No other official remediation or temporary fix is indicated. Patch status is confirmed fixed in these versions.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-17T16:59:42.759Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4ec4a7c9d9e3dbe3c8d53c
Added to database: 07/08/2026, 21:44:07 UTC
Last enriched: 07/16/2026, 10:05:25 UTC
Last updated: 08/19/2026, 22:52:13 UTC
Views: 79
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