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TI-2026-69574 Aliases CVE-2026-107586GHSA-q3hq-6rq3-6px5

Uncontrolled session eviction in hMailServer lets users end others' sessions

Priority LOW 20CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-770.

Summary

Progressive Robot hMailServer from 6.2.28 before 6.3.6 has uncontrolled eviction in the browser session table of its REST API, tracked as CWE-770. The shared session table drops its least recently used session when full, regardless of owner, and sets no limit on sessions per account. A remote authenticated user who repeatedly signs in with their own mailbox password can sign out other users' idle webmail and administration sessions for as long as they continue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00338 27th percentileScored 2026-11-07
Fix Fixed hMailServer (Progressive Robot Ltd): 6.3.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Progressive Robot LtdhMailServer6.2.28 to before 6.3.66.3.6Patch availableCNA
  • hMailServer VendorProgressive Robot Ltd Affected 6.2.28 to before 6.3.6 Fixed in 6.3.6 Patch available CNA

Remediation

Upgrade hMailServer to version 6.3.6, which fixes the flaw in the affected range from 6.2.28 before 6.3.6.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA hMailServer (Progressive Robot Ltd) Fixed in 6.3.6

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Progressive Robot hMailServer 6.3.6

    23 records Highest priority Priority LOW 23 LOW

    Other records, highest priority first

    • TI-2026-69567 Inefficient processing in hMailServer stalls mail deliveryPriority LOW 39
    • TI-2026-69565 Infinite loop in hMailServer MIME handling lets attackers stop mailPriority LOW 39
    • TI-2026-69564 Inefficient DKIM and ARC checks in hMailServer cause denial of servicePriority LOW 39
    Show all 23 records →

Timeline

  1. 2026-10-08 Threatist record created from CVE-2026-107586
  2. 2026-10-08 Alias added: GHSA-q3hq-6rq3-6px5
  3. 2026-10-09 CISA SSVC decision points changed

References

Other 2

  • TI-2026-64884 Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection') in hMailServer CVSS 3.1CRITICAL 9.8
  • TI-2026-76418 Unchecked loop limit in hMailServer lets remote attackers stop mail CVSS 3.1HIGH 7.5
  • TI-2026-69567 Inefficient processing in hMailServer stalls mail delivery CVSS 3.1HIGH 7.5
  • TI-2026-69565 Infinite loop in hMailServer MIME handling lets attackers stop mail CVSS 3.1HIGH 7.5
  • TI-2026-69564 Inefficient DKIM and ARC checks in hMailServer cause denial of service CVSS 3.1HIGH 7.5
  • TI-2026-69562 Inefficient JSON parsing in hMailServer lets attackers halt mail CVSS 3.1HIGH 7.5
See all 41 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences