Tunnelblick arbitrary file read via symlink following in tunnelblickd

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Summary

CVECVE-2026-31893
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-05 20:16:35 UTC
Updated2026-05-07 15:15:06 UTC
DescriptionTunnelblick 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.

Risk And Classification

Primary CVSS: v4.0 6.8 MEDIUM from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000080000 probability, percentile 0.006980000 (date 2026-05-12)

Problem Types: CWE-61 | CWE-61 CWE-61: UNIX Symbolic Link (Symlink) Following

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary6.8MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNADECLARED6.8MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
None
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Tunnelblick Tunnelblick affected >= 3.3beta26, < 9.0beta02 Not specified

References

ReferenceSourceLinkTags
github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02 [email protected] github.com
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