What is CVE-2025-66523?

CVE-2025-66523 is a medium-severity vulnerability in Foxit Esign, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-01-20.

How severe is CVE-2025-66523?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Foxit Esign

CVE-2025-66523

URL parameters are directly embedded into JavaScript code or HTML attributes without proper encoding or sanitization. This allows attackers to inject arbitrary scripts when an authenticated user visits a crafted link. This issue affects na1.foxitesign.foxit.com: before 2026‑01‑16.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.002 (5.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Foxit Esign
Foxit Software Inc. Na1.foxitesign.foxit.com — versions before 2026‑01‑16

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

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

Frequently asked questions

What is CVE-2025-66523?: CVE-2025-66523 is a medium-severity vulnerability in Foxit Esign, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-01-20.
How severe is CVE-2025-66523?: Medium severity. CVSS v3 base score is 6.1 out of 10.