{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.8.214"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "abf82ecc3ea85d53b319d27d3109560ff74d1173"
            }
          ],
          "repo": "https://github.com/freescout-help-desk/freescout",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-9ff4-mmhv-x6jp"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-639"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40591.json"
  },
  "details": "FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the phone-conversation creation flow accepts attacker-controlled `customer_id`, `name`, `to_email`, and `phone` values and resolves the target customer in the backend without enforcing mailbox-scoped customer visibility. As a result, a low-privileged agent who can create a phone conversation in Mailbox A can bind the new Mailbox A phone conversation to a hidden customer from Mailbox B and add a new alias email to that hidden customer record by supplying `to_email`. Version 1.8.214 fixes the vulnerability.",
  "id": "CVE-2026-40591",
  "modified": "2026-08-04T11:31:07.992851499Z",
  "published": "2026-04-21T16:54:14.113Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/freescout-help-desk/freescout/releases/tag/1.8.214"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40591.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40591"
    },
    {
      "type": "FIX",
      "url": "https://github.com/freescout-help-desk/freescout/commit/83eea1ca47d97c6cdc90c501734bc2579b014a34"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "FreeScout: Improper Authorization in Phone Conversation Creation Enables Cross-Mailbox Hidden Customer Modification"
}