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VulnerabilityPublished Updated

CVE-2025-2521: Honeywell C300 PCNT02 · Memory Buffer Overflow

Affects Honeywell C300 PCNT02Source CVE Database V5

0

Not known to be exploited · CVSS 8.6 High.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 42% 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:L/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
Fixed in–

AI-suggested

European organizations should prioritize immediate patching by upgrading to the latest Honeywell software versions as recommended: Experion PKS 520.2 TCU9 HF1, 530.1 TCU3 HF1, and OneWireless 322.5 and 331.1. In addition to patching, organizations should implement network segmentation to isolate industrial control systems from general IT networks and restrict access to trusted personnel only. Deploying intrusion detection and prevention systems tailored for industrial protocols can help detect anomalous activities indicative of exploitation attempts. Regularly auditing and monitoring system logs for unusual behavior is critical. Organizations should also enforce strict access controls and multi-factor authentication for remote access to these systems. Conducting thorough vulnerability assessments and penetration testing focused on industrial control environments will help identify residual risks. Finally, establishing incident response plans specific to industrial control system breaches will improve preparedness and minimize impact in case of exploitation.

Description

The Honeywell Experion PKS and OneWireless WDM contains a Memory Buffer vulnerability in the component Control Data Access (CDA). An attacker could potentially exploit this vulnerability, leading to an Overread Buffers, which could result in improper index validation against buffer borders 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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