Medium severity · published Apr 21, 2026
CVE-2026-40590
FreeScout's Customer AJAX Create Modifies Hidden Existing Customer
4.3
CVSS
0.2%
EPSS
No
On KEV
Description
FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the Change Customer modal exposes a “Create a new customer” flow via POST /customers/ajax with action=create. Under limited visibility, the endpoint drops unique-email validation. If the supplied email already belongs to a hidden customer, Customer::create() reuses that hidden customer object and fills empty profile fields from attacker-controlled input. Version 1.8.214 fixes the vulnerability.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
freescout · freescout-help-desk
< 1.8.214 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40590
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40590
github.com
https://github.com/freescout-help-desk/freescout/commit/b3d7611e6e173ed8a5e525b791deb6b32cf1ce62
github.com
https://github.com/freescout-help-desk/freescout/releases/tag/1.8.214
github.com
https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-wjw4-8xg6-342m
More from freescout
9.8
CVE-2026-40498
FreeScout has Authentication Bypass and Information Disclosure in SystemController via /system/cron
9.8
CVE-2026-27637
FreeScout's Predictable Authentication Token Enables Account Takeover
9.8
CVE-2025-48481
FreeScout Has Business Logic Errors
9.8
CVE-2025-48471
FreeScout Vulnerable to Arbitrary File Upload
9.4
CVE-2026-53595
FreeScout vulnerable to anonymous account takeover via /user-setup empty invite_hash on MySQL