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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.

PUBLISHED Reserved 2026-03-09 | Published 2026-05-05 | Updated 2026-05-05 | Assigner GitHub_M




MEDIUM: 6.8CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Problem types

CWE-61: UNIX Symbolic Link (Symlink) Following

Product status

>= 3.3beta26, < 9.0beta02
affected

References

github.com/...lblick/security/advisories/GHSA-927j-vcjf-hq69 exploit

github.com/...lblick/security/advisories/GHSA-927j-vcjf-hq69

github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02

cve.org (CVE-2026-31893)

nvd.nist.gov (CVE-2026-31893)

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