CVE-2026-40590 FreeScout's Customer AJAX Create Modifies Hidden Existing Customer
Attackers can modify hidden customer profiles by exploiting missing email validation in the customer creation flow.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-40590?
CVE-2026-40590 is a medium-severity vulnerability in freescout-help-desk freescout, published on 21 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-639
Which versions are affected by CVE-2026-40590?
How do I fix CVE-2026-40590?
No fix has been published for CVE-2026-40590 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-40590 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40590 exists.
Sources
Also known as GHSA-wjw4-8xg6-342m.