CVE-2026-40591

FreeScout: Improper Authorization in Phone Conversation Creation Enables Cross-Mailbox Hidden Customer Modification

HIGH
7.1
CVSS Score
Published: April 21, 2026 at 04:54 PM UTC
Updated: June 17, 2026 at 10:45 AM UTC
1 product affected across 1 vendorFreescout

Using freescout by freescout-help-desk?

Get instant alerts when new vulnerabilities affect freescout - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH7.1
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.8.214
Affected range stops below 1.8.214, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.1HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-639

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card