CVE-2026-31893 Tunnelblick arbitrary file read via symlink following in tunnelblickd
Local attackers can read arbitrary root-owned files via symlink following in Tunnelblick's helper process due to missing authorization and symlink validation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-31893?
CVE-2026-31893 is a medium-severity path traversal vulnerability in Tunnelblick, published on 5 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Tunnelblick is an open source graphic user interface for OpenVPN on macOS. In versions 3.3beta26 through 9.0beta01, any local user can read arbitrary root-owned files by exploiting a symlink following vulnerability in tunnelblick-helper, reachable through the world-accessible tunnelblickd Unix socket. The socket is configured with mode 0666, allowing any local user to connect. No authorization check is performed on the connecting client. The tunnelblick-helper process constructs a path to config.ovpn inside a user-controlled .tblk directory and reads it as root without symlink validation. An attacker can create a .tblk configuration with a symlinked config.ovpn pointing to any file and request tunnelblickd to read it. This issue has been fixed in versions 9.0beta02.
Weakness: CWE-61
Which versions are affected by CVE-2026-31893?
It affects 1 product.
Products include Tunnelblick Tunnelblick.
How do I fix CVE-2026-31893?
No fix has been published for CVE-2026-31893 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-31893 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31893 exists.
Sources
Also known as GHSA-927j-vcjf-hq69.