6.1

CVE-2026-55877: symfony ux Cross-site Scripting

CVSS: 6.1v3.1MediumAnalyzed
Published 08-07-2026Last modified 09-07-2026
Open JSON

Vulnerability summary

CVE-2026-55877 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in symfony ux. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 25.9% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
6.1/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.34%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 08-07-2026
    PublishedVulnerability first disclosed.
  2. 09-07-2026
    Last modifiedVulnerability information updated.

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 metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.34%

Chance of exploitation in the next 30 days

Percentile

26%

Versus all other CVEs

30-day change

0.00 pp

From 0.34% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.34%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Symfony1 product
  • ux≥ 2.17.0, < 2.36.1 | ≥ 3.0.0, < 3.2.0

1 vendor · 1 product

References

4 links