What is CVE-2025-66939?

CVE-2025-66939 is a medium-severity vulnerability in Altumcode 66biolinks, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-01-12.

How severe is CVE-2025-66939?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Altumcode 66biolinks

CVE-2025-66939

Cross Site Scripting vulnerability in 66biolinks by AltumCode v.61.0.1 allows an attacker to execute arbitrary code via a crafted favicon file

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-01-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (16.0th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 16.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000

Affected products

Altumcode 66biolinks — versions 61.0.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

66biolinks.com/ (Product)
gist.github.com/Waqar-Arain/2a21b135a04e7804c124688ea1085875 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2025-66939?: CVE-2025-66939 is a medium-severity vulnerability in Altumcode 66biolinks, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-01-12.
How severe is CVE-2025-66939?: Medium severity. CVSS v3 base score is 5.4 out of 10.