CVE-2026-40591

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.

The following products are affected by CVE-2026-40591 vulnerability.

Here, you will find a curated list of external links that provide in-depth information to CVE-2026-40591.

URL	Resource
https://github.com/freescout-help-desk/freescout/commit/83eea1ca47d97c6cdc90c501734bc2579b014a34
https://github.com/freescout-help-desk/freescout/releases/tag/1.8.214
https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp