Tunnelblick arbitrary file read via symlink following in tunnelblickd

{
  "id": "569c8e5e0aa6bd483f6f8f24935f01f7f8187691c4dc28b177c1a9c92f9f071d",
  "url": "https://osv.dev/vulnerability/CVE-2026-31893",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Tunnelblick arbitrary file read via symlink following in tunnelblickd",
    "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.",
    "evidence": "osv:CVE-2026-31893",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-31893",
      "aliases": [
        "CVE-2026-31893",
        "GHSA-927j-vcjf-hq69"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/tunnelblick/tunnelblick",
              "type": "GIT",
              "events": [
                {
                  "introduced": "553e3e99f73ad93620a37c87408c5d0838964310"
                },
                {
                  "fixed": "ba7d57c175c61caceb7faa66ca0bcc4d69ce0c77"
                },
                {
                  "introduced": "238dd15970955abe6f1b00208729ae2f9dd9c0e8"
                },
                {
                  "fixed": "035668b12ec19bfb1685cdb871f377314eb9255d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:tunnelblick:tunnelblick:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.5.3"
                      },
                      {
                        "fixed": "8.0.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta01:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "8.1-beta01"
                      },
                      {
                        "last_affected": "8.1-beta01"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta02:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "8.1-beta02"
                      },
                      {
                        "last_affected": "8.1-beta02"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:tunnelblick:tunnelblick:8.1:beta03:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "8.1-beta03"
                      },
                      {
                        "last_affected": "8.1-beta03"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:tunnelblick:tunnelblick:9.0:beta01:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "9.0-beta01"
                      },
                      {
                        "last_affected": "9.0-beta01"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "range": [
                      {
                        "fixed": "035668b12ec19bfb1685cdb871f377314eb9255d"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v9.0beta02"
                  }
                ]
              }
            }
          ],
          "versions": [
            "8.1-beta01",
            "8.1-beta02",
            "8.1-beta03",
            "9.0-beta01",
            "v9.0beta01",
            "v8.1beta03",
            "v8.1beta02",
            "v8.1beta01"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31893.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:28.001528203Z",
      "provider": "osv",
      "references": [
        "https://github.com/Tunnelblick/Tunnelblick/releases/tag/v9.0beta02",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31893.json",
        "https://github.com/Tunnelblick/Tunnelblick/security/advisories/GHSA-927j-vcjf-hq69",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31893"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-61"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31893.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-31893",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 494680,
  "published_at": "2026-05-05T18:55:41.737+00:00"
}