CVE-2026-40592 FreeScout's cross-user undo reply allows mailbox peers to recall another agent's outbound reply
An attacker can recall another agent's sent reply in FreeScout due to missing ownership checks on the undo route.
- 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-2026-40592?
CVE-2026-40592 is a medium-severity missing authorization 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 undo-send route `GET /conversation/undo-reply/{thread_id}` checks only whether the current user can view the parent conversation. It does not verify that the current user created the reply being undone. In a shared mailbox, one agent can therefore recall another agent's just-sent reply during the 15-second undo window. Version 1.8.214 fixes the vulnerability.
Weakness: CWE-862
Which versions are affected by CVE-2026-40592?
How do I fix CVE-2026-40592?
No fix has been published for CVE-2026-40592 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-40592 being exploited?
There is no known exploitation of CVE-2026-40592 in the wild and no public exploit code.
Sources
Also known as GHSA-674v-r6xp-mvp6.