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Description

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.

PUBLISHED Reserved 2026-04-14 | Published 2026-04-21 | Updated 2026-04-21 | Assigner GitHub_M




HIGH: 7.1CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N

Problem types

CWE-639: Authorization Bypass Through User-Controlled Key

Product status

< 1.8.214
affected

References

github.com/...escout/security/advisories/GHSA-9ff4-mmhv-x6jp exploit

github.com/...escout/security/advisories/GHSA-9ff4-mmhv-x6jp

github.com/...ommit/83eea1ca47d97c6cdc90c501734bc2579b014a34

github.com/...scout-help-desk/freescout/releases/tag/1.8.214

cve.org (CVE-2026-40591)

nvd.nist.gov (CVE-2026-40591)

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