CVE-2026-31893 PUBLISHED

Tunnelblick arbitrary file read via symlink following in tunnelblickd

Assigner: GitHub_M
Reserved: 09.03.2026 Published: 05.05.2026 Updated: 05.05.2026

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.

Metrics

CVSS 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
CVSS Score: 6.8

Product Status

Vendor Tunnelblick
Product Tunnelblick
Versions
  • Version >= 3.3beta26, < 9.0beta02 is affected

References

Problem Types

  • CWE-61: UNIX Symbolic Link (Symlink) Following CWE