CVE-2026-40591

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data tampering.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-04-21 17:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 10:45 UTC Last updatedMost recent change to the record

Details

Published

2026-04-21 17:16 UTC

Last modified

2026-06-17 10:45 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-639 · Insecure direct object reference

Record status

Deferred

Attack profile CVSS 3.1 · 7.1

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

High

Availability

None