CVE-2026-40591

High

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.

SeverityHigh
CVSS7.1
Exploit probability—
ProductFreescout
PublishedApr 21, 2026
First seenApr 21, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
freescout-help-desk freescout< 1.8.214—

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.