FKIE_CVE-2026-31893

Vulnerability from fkie_nvd - Published: 2026-05-05 20:16 - Updated: 2026-06-17 10:34
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Summary
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.
References
security-advisories@github.comhttps://github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02Product, Release Notes
security-advisories@github.comhttps://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69Exploit, Vendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69Exploit, Vendor Advisory
Impacted products
Vendor Product Version
tunnelblick tunnelblick *
tunnelblick tunnelblick 3.3
tunnelblick tunnelblick 8.1
tunnelblick tunnelblick 8.1
tunnelblick tunnelblick 8.1
tunnelblick tunnelblick 9.0
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "Tunnelblick",
          "vendor": "Tunnelblick",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.3beta26, \u003c 9.0beta02"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:tunnelblick:tunnelblick:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "0091B93B-5FCA-4B34-8578-6D73399E5D7B",
              "versionEndExcluding": "8.0.1",
              "versionStartIncluding": "3.5.3",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:tunnelblick:tunnelblick:3.3:beta26:*:*:*:*:*:*",
              "matchCriteriaId": "DA65FDFE-43E0-4846-B674-4EF26613E294",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta01:*:*:*:*:*:*",
              "matchCriteriaId": "E86DA6F9-1B0E-496D-B000-3B53F32F46F9",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta02:*:*:*:*:*:*",
              "matchCriteriaId": "5EEBCC0A-309F-4BF1-8B8E-548588FD9418",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta03:*:*:*:*:*:*",
              "matchCriteriaId": "F94C886A-E185-4A58-B072-56B4D0FA7FAC",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:tunnelblick:tunnelblick:9.0:beta01:*:*:*:*:*:*",
              "matchCriteriaId": "3BBF415C-6088-4399-B99F-421E08CD79A1",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "id": "CVE-2026-31893",
  "lastModified": "2026-06-17T10:34:42.660",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "LOCAL",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "LOW",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "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",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-31893",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-05T19:37:28.228929Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-05-05T20:16:35.373",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "url": "https://github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "url": "https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-61"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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