# CVE-2026-114472: Insufficient Resource Pool in hMailServer


- **Severity:** Low 3.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 21 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-m7x4-4w88-7g5p

## What is CVE-2026-114472?

CVE-2026-114472 is a low-severity vulnerability in Progressive Robot Ltd hMailServer, published on 21 Oct 2026. 

### Official description

Insufficient resource pool in the ACME HTTP-01 challenge responder of Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to cause a certificate issuance or renewal to fail. When the server obtains or renews a TLS certificate over ACME it runs an HTTP-01 challenge responder on port 80 for the certificate authority to read the challenge token; the responder served one connection at a time, accepting a socket, waiting up to five seconds to receive a request, answering it, and only then accepting the next. A client that connected and sent nothing held the single worker for the whole timeout, so enough idle connections during a validation keep the certificate authority's own request from being answered in time and the validation fails. Sustained across a certificate's renewals this leads to the certificate expiring, after which clients refuse the server's TLS; the mail service itself continues on its current certificate until then. No authentication is required to connect to the responder. Version 6.3.7 serves up to 64 connections at once and closes a connection past that, so that where a handful of idle connections, one after another, sufficed before, a client must keep 64 idle connections open at once throughout a validation to have the certificate authority's connection closed.

Weakness: CWE-410 (Insufficient Resource Pool)

## Which versions are affected by CVE-2026-114472?


## How do I fix CVE-2026-114472?

No fix has been published for CVE-2026-114472 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-114472 being exploited?

There is no known exploitation of CVE-2026-114472 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-114472 and fix it if it is affected.

What it is: CVE-2026-114472 is a low-severity vulnerability in Progressive Robot Ltd hMailServer, published on 21 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-114472 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-2026-114472/ (Markdown: https://insights.sbomify.com/CVE-2026-114472/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-114472
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-114472
- OSV: https://osv.dev/vulnerability/CVE-2026-114472

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-114472/
Summaries are generated and may contain mistakes; the official description above is the record.