CVE-2026-31893Public exploit

Local root-owned file disclosure via symlink following

Published May 5, 2026 · Updated May 5, 2026

Symlink following in Tunnelblick 3.3beta26 through 9.0beta01 allows local users to read arbitrary root-owned files. tunnelblick-helper constructs a config.ovpn path inside a user-controlled .tblk directory and reads the target as root without rejecting symbolic links. A mode-0666 tunnelblickd Unix socket accepts the request without authorizing the local client, exposing file contents but not file modification.

CVSS severity6.8
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Symlink following in Tunnelblick 3.3beta26 through 9.0beta01 allows local users to read arbitrary root-owned files. tunnelblick-helper constructs a config.ovpn path inside a user-controlled .tblk directory and reads the target as root without rejecting symbolic links. A mode-0666 tunnelblickd Unix socket accepts the request without authorizing the local client, exposing file contents but not file modification.

The record

CVE
CVE-2026-31893
Published
May 5, 2026
Updated
May 5, 2026
Vendor
The Tunnelblick Project
Product
Tunnelblick
Classifications
CWE-61, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 5, 2026CVE publishedPublication date reported by the CVE source.
  2. May 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.3beta26, < 9.0beta02

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Tunnelblick Project · Tunnelblickversion=>= 3.3beta26, < 9.0beta02

Published CVSS scores

6.5GitHub Security AdvisoryCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
6.8GitHub, Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-61UNIX Symbolic Link (Symlink) Following
T1005Data from Local System

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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