TI-2026-29327 Aliases CVE-2026-40591

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

MEDIUM 64CWE-639Published 2026-04-21 · Updated 2026-04-21

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: Low · High · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-639.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00211 11th percentileScored 2026-11-07

Fix Fixed freescout (freescout-help-desk): 1.8.214

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
freescout-help-desk	freescout	before 1.8.214	1.8.214	Patch available	CNA

freescout Vendorfreescout-help-desk Affected before 1.8.214 Fixed in 1.8.214 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:freescout:freescout::::::::	—	—	freescout-help-desk

cpe:2.3:a:freescout:freescout:*:*:*:*:*:*:*:* Versions — — ·freescout-help-desk

Remediation

Fix · CNA freescout (freescout-help-desk) Fixed in 1.8.214

Timeline

2026-10-02 Threatist record created from CVE-2026-40591

References

Other 3

TI-2026-38652 FreeScout vulnerable to anonymous account takeover via /user-setup empty invite_hash on MySQL CVSS 3.1CRITICAL 9.4
TI-2026-22019 FreeScout's Predictable Authentication Token Enables Account Takeover CVSS 3.1CRITICAL 9.8
TI-2026-30304 FreeScout's user invitation hash never expires: permanent unauthenticated account takeover if invite link leaks CVSS 3.1CRITICAL 9.1
TI-2026-29249 FreeScout has Authentication Bypass and Information Disclosure in SystemController via /system/cron CVSS 4.0HIGH 8.9
TI-2026-29247 FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Download via Brute Force CVSS 4.0HIGH 8.8
TI-2026-38648 FreeScout Vulnerable to Unauthenticated Conversation Thread Injection via HMAC Length Bypass in FetchEmails CVSS 3.1HIGH 8.6

See all 90 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences