CVE-2026-31893

Tunnelblick arbitrary file read via symlink following in tunnelblickd

Published May 5, 2026 CVSS 4.0 · 6.8 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:tunnelblick:tunnelblick:*:*:*:*:*:*:*:*
cpe:2.3:a:tunnelblick:tunnelblick:3.3:beta26:*:*:*:*:*:*
cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta01:*:*:*:*:*:*
cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta02:*:*:*:*:*:*
cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta03:*:*:*:*:*:*
cpe:2.3:a:tunnelblick:tunnelblick:9.0:beta01:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'}

Type Values Removed Values Added
First Time appeared Tunnelblick
Tunnelblick tunnelblick
Vendors & Products Tunnelblick
Tunnelblick tunnelblick
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Tunnelblick arbitrary file read via symlink following in tunnelblickd
Weaknesses CWE-61
References
Metrics cvssV4_0

{'score': 6.8, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 5, 2026, 7:37 PM
Reserved
Mar 9, 2026, 9:59 PM
Status
Analyzed
Published
May 5, 2026, 8:16 PM
Modified
Jul 25, 2026, 11:10 AM