CVE-2026-107586 Allocation of Resources Without Limits or Throttling in hMailServer
An authenticated user can exhaust the shared session table, forcibly logging out other users and administrators from the webmail and admin interfaces.
- 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-2026-107586?
CVE-2026-107586 is a medium-severity denial of service vulnerability in Progressive Robot Ltd hMailServer, published on 8 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Uncontrolled eviction in the browser session table of the REST API in Progressive Robot hMailServer 6.2.28 through 6.3.5 allows a remote authenticated user to end other users' sessions. The table of browser sessions, shared by every account, the server administrator and support sessions, dropped its least recently used session whenever it was full, whoever it belonged to, and placed no limit on how many sessions one account could hold. A user who repeatedly signs in with their own mailbox password can therefore keep the table full and sign out every webmail and administration session that is idle for more than a short time, for as long as they continue.
Weakness: CWE-770
Which versions are affected by CVE-2026-107586?
How do I fix CVE-2026-107586?
No fix has been published for CVE-2026-107586 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-107586 being exploited?
There is no known exploitation of CVE-2026-107586 in the wild and no public exploit code.
Sources
Also known as GHSA-q3hq-6rq3-6px5.