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TI-2026-84999 Aliases CVE-2026-110022GHSA-3922-7ccf-5hwx

Signature check bypass in Phoenix Contact PLCnext Engineer

Priority LOW 38CWE-494Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-494.

Summary

Phoenix Contact PLCnext Engineer from 0.0 before 2026.6 is affected. Its plugin deployment routine processes archive entries that the signature verification never covers, so unsigned code can pass as part of a signed plugin package (CWE-494). An unauthenticated local attacker can overwrite a signed assembly with an unsigned DLL, and the plugin loader then runs that code, which leads to full compromise of the affected system.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00108 1st percentileScored 2026-11-07
Fix Fixed PLCnext Engineer (Phoenix Contact): 2026.6

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Phoenix ContactPLCnext Engineer0.0 to before 2026.62026.6Patch availableCNA
  • PLCnext Engineer VendorPhoenix Contact Affected 0.0 to before 2026.6 Fixed in 2026.6 Patch available CNA

Remediation

Upgrade Phoenix Contact PLCnext Engineer to version 2026.6.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

  • Fix · CNA PLCnext Engineer (Phoenix Contact) Fixed in 2026.6

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Phoenix Contact PLCnext Engineer 2026.6

    3 records Highest priority Priority LOW 3 LOW

    Other records, highest priority first

    • TI-2026-85000 Path traversal in Phoenix Contact PLCnext Engineer plug-in deploymentPriority LOW 38
    • TI-2026-84998 Phoenix Contact PLCnext Engineer: missing GSDX SignatureValue verificationPriority LOW 29
    Show all 3 records →

Timeline

  1. 2026-11-04 Threatist record created from CVE-2026-110022
  2. 2026-11-04 Alias added: GHSA-3922-7ccf-5hwx
  3. 2026-11-04 CISA SSVC decision points changed
  4. 2026-11-04 Priority changed: MEDIUM → LOW

References

Other 1

  • TI-2014-07463 Phoenix Contact Software ProConOs and MultiProg Missing Authentication for Critical Function CVSS 2.0CRITICAL 10.0
  • TI-2024-17093 PHOENIX CONTACT: Remote code execution in CHARX Series CVSS 3.1CRITICAL 9.8
  • TI-2022-13692 Insufficient Verification of Data Vulnerability in PHOENIX CONTACT classic line industrial controllers CVSS 3.1CRITICAL 9.8
  • TI-2026-21959 Remote code execution via uploading a malicious IODD file CVSS 3.1CRITICAL 9.8
  • TI-2026-21940 Authentication Bypass in _account_log CVSS 3.1CRITICAL 9.8
  • TI-2023-03334 PHOENIX CONTACT: OS Command Injection in WP 6xxx Web panels CVSS 3.1CRITICAL 10.0
See all 194 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences