CVE-2026-107586

Medium

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.

SeverityMedium
CVSS4.3
Exploit probability—
ProducthMailServer
PublishedOct 8, 2026
First seenOct 8, 2026

How to fix

Update
  • Progressive Robot Ltd hMailServer6.3.6 or later

Affected products

ProductAffected versionsFixed in
Progressive Robot Ltd hMailServer6.2.28 ≤ v < 6.3.66.3.6

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