What is CVE-2025-66521?

CVE-2025-66521 is a medium-severity vulnerability in Foxit Pdf Editor Cloud, classified under Cross-site Scripting. CVSS score: 6.3/10. Published 2025-12-19.

How severe is CVE-2025-66521?

Medium severity. CVSS v3 base score is 6.3 out of 10.

XSS in Foxit Pdf Editor Cloud

CVE-2025-66521

A stored cross-site scripting (XSS) vulnerability exists in pdfonline.foxit.com within the Trusted Certificates feature. A crafted payload can be injected as the certificate name, which is later rendered into the DOM without proper sanitization. As a result, the injected script executes each time the Trusted Certificates view is loaded.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.001 (1.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N.

Affected products

Foxit Pdf_editor_cloud
Foxit Software Inc. Pdfonline.foxit.com — versions before 2025‑12‑01

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

14984358-7092-470d-8f34-ade47a7658a2 (Vendor Advisory)

Frequently asked questions

What is CVE-2025-66521?: CVE-2025-66521 is a medium-severity vulnerability in Foxit Pdf Editor Cloud, classified under Cross-site Scripting. CVSS score: 6.3/10. Published 2025-12-19.
How severe is CVE-2025-66521?: Medium severity. CVSS v3 base score is 6.3 out of 10.