Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Tunnelblick | Tunnelblick | >= 3.5.3, < 8.0.1 |
Related Weaknesses (CWE)
References
- https://github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02ProductRelease Notes
- https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hqExploitVendor Advisory
- https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hqExploitVendor Advisory
FAQ
What is CVE-2026-31893?
CVE-2026-31893 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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...
How severe is CVE-2026-31893?
CVE-2026-31893 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-31893?
Check the references section above for vendor advisories and patch information. Affected products include: Tunnelblick Tunnelblick.