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.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02	Product Release Notes
https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69	Exploit Vendor Advisory
https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

OR	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::::::

History

No history.

Information

Published : 2026-05-05 20:16

Updated : 2026-07-25 11:10

NVD link : CVE-2026-31893

Mitre link : CVE-2026-31893

CVE.ORG link : CVE-2026-31893

JSON object : View

Products Affected

tunnelblick

tunnelblick

CWE

CWE-61

UNIX Symbolic Link (Symlink) Following

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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."}, {"lang": "es", "value": "Tunnelblick es una interfaz gr\u00e1fica de usuario de c\u00f3digo abierto para OpenVPN en macOS. En las versiones 3.3beta26 hasta la 9.0beta01, cualquier usuario local puede leer archivos arbitrarios propiedad de root explotando una vulnerabilidad de seguimiento de symlink en tunnelblick-helper, accesible a trav\u00e9s del socket Unix tunnelblickd de acceso global. El socket est\u00e1 configurado con el modo 0666, permitiendo que cualquier usuario local se conecte. No se realiza ninguna comprobaci\u00f3n de autorizaci\u00f3n en el cliente que se conecta. El proceso tunnelblick-helper construye una ruta a config.ovpn dentro de un directorio .tblk controlado por el usuario y lo lee como root sin validaci\u00f3n de symlink. Un atacante puede crear una configuraci\u00f3n .tblk con un config.ovpn con symlink apuntando a cualquier archivo y solicitar a tunnelblickd que lo lea. Este problema ha sido solucionado en las versiones 9.0beta02."}], "lastModified": "2026-07-25T11:10:00.100", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:tunnelblick:tunnelblick:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0091B93B-5FCA-4B34-8578-6D73399E5D7B", "versionEndExcluding": "8.0.1", "versionStartIncluding": "3.5.3"}, {"criteria": "cpe:2.3:a:tunnelblick:tunnelblick:3.3:beta26:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DA65FDFE-43E0-4846-B674-4EF26613E294"}, {"criteria": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta01:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E86DA6F9-1B0E-496D-B000-3B53F32F46F9"}, {"criteria": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta02:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5EEBCC0A-309F-4BF1-8B8E-548588FD9418"}, {"criteria": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta03:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F94C886A-E185-4A58-B072-56B4D0FA7FAC"}, {"criteria": "cpe:2.3:a:tunnelblick:tunnelblick:9.0:beta01:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3BBF415C-6088-4399-B99F-421E08CD79A1"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}