CVE-2025-66520: Foxit pdfonline.foxit.com Stored Cross-Site Scripting in Portfolio SVG Handling

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-19 · updated 2026-06-17
Weakness: CWE-79

Description

A stored cross-site scripting (XSS) vulnerability exists in the Portfolio feature of the Foxit PDF Editor cloud (pdfonline.foxit.com). User-supplied SVG files are not properly sanitized or validated before being inserted into the HTML structure. As a result, embedded HTML or JavaScript within a crafted SVG may execute whenever the Portfolio file list is rendered.

Affected products

Foxit Pdf Editor Cloud: before 2025-12-01 — fixed in 2025-12-01

How to fix

Upgrade to a fixed version: Foxit Pdf Editor Cloud 2025-12-01. Check the vendor advisory for mitigations.

References

https://www.foxit.com/support/security-bulletins.html

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