Vulnerability · Published May 5, 2026 · Assigned by GitHub_M
CVE-2026-31893Tunnelblick arbitrary file read via symlink following in tunnelblickd
Medium 6.8
In plain English
A medium-severity security flaw in Tunnelblick from Tunnelblick. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities).
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Tunnelblick | Tunnelblick | >= 3.3beta26, < 9.0beta02 |
Weakness: CWE-61 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69 x_refsource_CONFIRM
- https://github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02 x_refsource_MISC