CVE-2026-40589 FreeScout has Customer Edit Cross-Mailbox Email Takeover
Low-privileged agents can hijack hidden customer emails and conversations across mailboxes, exposing private data and modifying records.
- 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-2026-40589?
CVE-2026-40589 is a high-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, a low-privileged agent can edit a visible customer and add an email address already owned by a hidden customer in another mailbox. The server discloses the hidden customer’s name and profile URL in the success flash, reassigns the hidden email to the visible customer, and rebinds hidden-mailbox conversations for that email to the visible customer. Version 1.8.214 fixes the issue.
Weakness: CWE-639
Which versions are affected by CVE-2026-40589?
How do I fix CVE-2026-40589?
No fix has been published for CVE-2026-40589 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-40589 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40589 exists.
Sources
Also known as GHSA-mv55-3mgv-fxwr.