# 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.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Oct 2026
- **Updated:** 8 Oct 2026
- **Also known as:** GHSA-q3hq-6rq3-6px5

## 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 (Allocation of Resources Without Limits or Throttling)

## 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.

## Is CVE-2026-107586 being exploited?

There is no known exploitation of CVE-2026-107586 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107586 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-107586 in the wild and no public exploit code.

Affected product: Progressive Robot Ltd hMailServer. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-107586/ (Markdown: https://insights.sbomify.com/CVE-2026-107586/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107586
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107586
- OSV: https://osv.dev/vulnerability/CVE-2026-107586

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107586/
Summaries are generated and may contain mistakes; the official description above is the record.