CVE-2025-66003 Local users can perform a local root exploit via smb4k mounthelper
Local attackers can escalate privileges to root via path traversal in smb4k mounthelper by controlling Samba share contents.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-66003?
CVE-2025-66003 is a high-severity path traversal vulnerability in https://github.com/KDE/ smb4k, published on 8 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An External Control of File Name or Path vulnerability in smb4k allowsl ocal users to perform a local root exploit via smb4k mounthelper if they can access and control the contents of a Samba shareThis issue affects smb4k: from ? before 4.0.5.
Weakness: CWE-73
Which versions are affected by CVE-2025-66003?
How do I fix CVE-2025-66003?
Upgrade to a fixed version.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2025-66003 being exploited?
There is no known exploitation of CVE-2025-66003 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2025-66003, GHSA-c32g-xjp2-p4pw, UBUNTU-CVE-2025-66003.