CVE-2026-107586: CWE-770: Allocation of Resources Without Limits or Throttling in Progressive Robot Ltd hMailServer
Description
CVE-2026-107586 is a medium severity vulnerability in Progressive Robot Ltd hMailServer versions 6.2.28 through 6.3.5. It involves uncontrolled eviction in the browser session table of the REST API, allowing a remote authenticated user to forcibly end other users' sessions by filling the session table. This occurs because the session table, shared among all accounts including administrators, evicts the least recently used session when full without limiting the number of sessions per account.
CVSS v3.1
Score 4.3medium
Affected software
Progressive Robot Ltd
hMailServer
pkg:github/hmailserver/hmailserverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in Progressive Robot Ltd hMailServer (versions >=6.2.28 <6.3.6) arises from the browser session table used by the REST API. This table is shared across all user accounts, including server administrators and support sessions. When the table reaches capacity, it evicts the least recently used session regardless of ownership. Since there is no limit on how many sessions a single account can hold, a remote authenticated user can repeatedly sign in to their mailbox, filling the session table and causing other users' idle sessions to be evicted. This results in denial of service by forcing other users to be signed out.
Potential Impact
The impact is limited to availability, specifically causing denial of service by terminating other users' webmail and administration sessions. There is no confidentiality or integrity impact. The vulnerability requires remote authenticated access and does not require user interaction.
Mitigation Recommendations
No official patch or fix is currently documented. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, monitoring and limiting session creation per user, if possible, may help mitigate the impact. No vendor advisory content is provided stating 'no action required' or 'already mitigated'.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitLab
- Date Reserved
- 2026-10-08T10:52:35.638Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ac7b46a2cdf04f656230dc9
Added to database: 10/08/2026, 15:19:06 UTC
Last enriched: 10/08/2026, 15:33:33 UTC
Last updated: 10/08/2026, 15:36:12 UTC
Views: 4
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