---
id: "CVE-2026-112356"
kind: "vulnerability"
aliases: ["CVE-2026-112356"]
title: "Kerio Connect Webmail: crafted email injects script into victim's session"
severity: "medium"
cvss: 6.1
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["email", "kerio-connect", "package", "self-hosted", "webmail"]
not_affected_if: ["patched-version"]
published_at: "2026-10-28T16:17:01+00:00"
first_seen_at: "2026-10-28T16:33:49+00:00"
updated_at: "2026-10-28T16:35:57+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112356", "first_seen_at": "2026-10-28T16:33:49+00:00"}]
---

# Kerio Connect Webmail: crafted email injects script into victim's session

Kerio Connect versions before 10.0.9 Patch 2 have a cross-site scripting flaw in Webmail's link auto-formatter, which re-processes text already inside a link. A remote attacker who sends a crafted email can break out of the href attribute and run script in the victim's authenticated Webmail session.

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

## How to check

- Check the installed Kerio Connect version in the admin console or on the server; unknown if the sources give a exact command.
- Confirm whether Webmail is in use by your users.

## Fix

- Upgrade Kerio Connect to `10.0.9 Patch 2` or later.

## Timeline

- 2026-10-28T16:33:49+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-112356

## From the sources

GFI KerioConnect (Kerio Connect) before 10.0.9 Patch 2 contains a cross-site scripting vulnerability in the Webmail component that allows a remote attacker to spoof link targets or inject HTML into a message as rendered in a victim's authenticated Webmail session by sending a crafted email whose text is already inside a link. Attackers can exploit the link auto-formatter's re-processing of already-linked text, using quote characters to break out of the href attribute and inject attacker-controlled markup to execute script in the victim's session.

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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_