Vulnerability in Tunnelblick
CVE-2026-31893
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.002 (7.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 7.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: -0.001
Affected products
- Tunnelblick — versions 9.0, 3.3, 8.1
Weakness classification (CWE)
References
- github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69 (Exploit, Vendor Advisory)
- github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-31893?
- CVE-2026-31893 is a medium-severity vulnerability in Tunnelblick, classified under UNIX Symbolic Link (Symlink) Following. CVSS score: 5.5/10. Published 2026-05-05.
- How severe is CVE-2026-31893?
- Medium severity. CVSS v3 base score is 5.5 out of 10.