CVE-2025-66939 Cross-site scripting in n/a

Medium 5.4 Published 12 Jan 2026 Updated 12 Jan 2026

An attacker can execute arbitrary code via a crafted favicon file in 66biolinks, potentially compromising user sessions or data.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2025-66939?

CVE-2025-66939 is a medium-severity cross-site scripting vulnerability in n/a, published on 12 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

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

Weakness: CWE-79

Which versions are affected by CVE-2025-66939?

It affects 1 product.

Products include Altumcode 66biolinks.

How do I fix CVE-2025-66939?

No fix has been published for CVE-2025-66939 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-66939 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-66939 exists.

Sources

Also known as GHSA-g579-x2p7-hjfv.