What is CVE-2026-107586?

CVE-2026-107586 is a medium-severity vulnerability in Progressive Robot Ltd Hmailserver, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 4.3/10. Published 2026-10-08.

How severe is CVE-2026-107586?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Resource exhaustion in Progressive Robot Ltd Hmailserver

CVE-2026-107586

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.

Published 2026-10-08.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Progressive Robot Ltd Hmailserver

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

Frequently asked questions

What is CVE-2026-107586?: CVE-2026-107586 is a medium-severity vulnerability in Progressive Robot Ltd Hmailserver, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 4.3/10. Published 2026-10-08.
How severe is CVE-2026-107586?: Medium severity. CVSS v3 base score is 4.3 out of 10.