---
id: "CVE-2026-114479"
kind: "vulnerability"
aliases: ["CVE-2026-114479"]
title: "hMailServer: infected single-part messages delivered unchanged when attachments are stripped"
severity: "medium"
cvss: 5.8
epss: 0.00321
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["hmailserver", "mail-server", "package", "self-hosted"]
not_affected_if: ["default-config", "virus-scanning-disabled"]
published_at: "2026-10-21T16:17:35+00:00"
first_seen_at: "2026-10-23T21:57:29+00:00"
updated_at: "2026-10-25T04:10:06+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114479", "first_seen_at": "2026-10-23T21:57:29+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114479", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# hMailServer: infected single-part messages delivered unchanged when attachments are stripped

When hMailServer's virus scanner is set to strip attachments and deliver the text, messages whose only part is a non-text file, archive, or whole message are delivered as they arrived, infected content included. Any remote sender can trigger it, and the recipient's mail client may then open the infected content.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the virus scanning action in hMailServer Administrator: if it is set to remove attachments and deliver the text (not the default delete), the installation is exposed.
- Confirm the version is between `6.0.0` and `6.3.6`.

## Fix

- Upgrade hMailServer to a version later than `6.3.6`; the sources do not name the fixed version, so check the vendor release notes.
- Until patched, change the virus scanner action from remove attachments to delete the message.

## Timeline

- 2026-10-23T21:57:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114479
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114479

## From the sources

Not failing securely in the anti-virus attachment-stripping action of Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to have a message that the server's virus scanner found infected delivered to the recipient's mailbox unchanged. With virus scanning enabled and its action set to remove attachments and deliver the text (the default action deletes the message), the server keeps one text part of an infected message and replaces every attachment with a note. A message whose single part is not text - a program or an archive sent as the whole message, a message carried whole, a file declared an attachment, or an S/MIME message signed as one part, whose content the recipient's mail client opens - had no part the action could pick out, and was delivered as it arrived, with the content the scanner had found and nothing but a line in the application log to show it. Any sender can write such a message.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_