---
id: CVE-2026-110022
title: Signed plug-in validation bypass
summary: >-
  The PFI plugin framework deploys executable assemblies (DLLs) from a signed
  plugin package into the local plugin repository and loads them via reflection,
  but the deployment routine processes archive entries that were never covered
  by th…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-494
vendor: Phoenix Contact
product: PLCnext Engineer
affected:
  - plcnext_engineer >= 0.0 < 2026.6
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-11-04T20:10:17.506128Z'
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T20:10:32.499Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-110022'
references:
  - url: 'https://www.certvde.com/en/advisories/VDE-2026-121/'
tags:
  - cve.org
epss: 0.00108
epssPercentile: 0.01195
ingestedAt: '2026-11-05T21:36:00.531Z'
---

## Overview

The PFI plugin framework deploys executable assemblies (DLLs) from a signed plugin package into the local plugin repository and loads them via reflection, but the deployment routine processes archive entries that were never covered by the signature verification. An unauthenticated local attacker can replace an unsigned DLL outside the signed prefix in the archive passes verification and overwrites the legitimate signed assembly at the same destination path. The plugin loader then instantiates the attacker-supplied code without any additional integrity check resulting in a full compromise of the affected systems.

## Affected

- `plcnext_engineer >= 0.0 < 2026.6`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.