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VulnerabilityPublished Updated

CVE-2025-3946: Honeywell C300 PCNT02 · Deployment of Wrong Handler

Affects Honeywell C300 PCNT02Source CVE Database V5

0

Not known to be exploited · CVSS 8.2 High.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Honeywell C300 PCNT02Affected
  • =520.1
  • =530
  • <=520.2-tcu9
  • <=530-tcu3
  • >=322.1 <=322.4
  • >=330.1 <=330.3
Fixed in–

AI-suggested

European organizations should prioritize immediate patching by upgrading to the Honeywell recommended versions: Experion PKS 520.2 TCU9 HF1, 530.1 TCU3 HF1, and OneWireless 322.5 and 331.1. Beyond patching, network segmentation should be enforced to isolate industrial control systems from general IT networks and the internet, reducing exposure to remote attacks. Implement strict access controls and monitoring on the Control Data Access (CDA) components to detect anomalous packet handling or unexpected network traffic patterns. Deploy intrusion detection and prevention systems (IDS/IPS) tailored for industrial protocols to identify exploitation attempts. Regularly audit and validate system configurations to ensure no unauthorized changes to handlers or packet processing modules occur. Conduct thorough incident response exercises simulating this vulnerability exploitation to prepare operational teams. Additionally, maintain up-to-date asset inventories to quickly identify affected devices and verify patch status. Collaborate with Honeywell support for guidance and monitor threat intelligence feeds for emerging exploit information. Finally, consider implementing application whitelisting and strict code execution policies on control system hosts to limit the impact of potential remote code execution.

Description

The Honeywell Experion PKS and OneWireless WDM contains a Deployment of Wrong Handler vulnerability in the component Control Data Access (CDA). An attacker could potentially exploit this vulnerability, leading to Input Data Manipulation, which could result in incorrect handling of packets leading to remote code execution. Honeywell recommends updating to the most recent version of Honeywell Experion PKS:520.2 TCU9 HF1 and 530.1 TCU3 HF1 and OneWireless: 322.5 and 331.1. The affected Experion PKS products are C300 PCNT02, C300 PCNT05, FIM4, FIM8, UOC, CN100, HCA, C300PM, and C200E. The Experion PKS versions affected are from 520.1 through 520.2 TCU9 and from 530 through 530 TCU3. The OneWireless WDM affected versions are 322.1 through 322.4 and 330.1 through 330.3.

References

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