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Fencer Vulns
high 8.2

CVE-2025-3947 json

Integer underflow during processing of short network packets in CDA FTEB responder

published 2025-07-10 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-21065

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

The Honeywell Experion PKS contains an Integer Underflow

vulnerability

in the component Control Data Access (CDA). An attacker could potentially exploit this vulnerability, leading to

Input Data Manipulation, which could result in improper integer data value checking during subtraction leading to a denial of service.

Honeywell recommends updating to the most recent version of Honeywell Experion PKS:520.2 TCU9 HF1 and 530.1 TCU3 HF1.

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.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-25-205-03 updated cvss 8.2

Honeywell Experion PKS (Update A)

  • Honeywell Experion PKS <R520.2_TCU9_Hot_Fix_1, <R530_TCU3_Hot_Fix_1
    affected: vendor fix process.honeywell.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Affected products

  • Honeywell C300 PCNT02
  • Honeywell C300 PCNT05
  • Honeywell FIM4
  • Honeywell FIM8
  • Honeywell UOC
  • Honeywell CN100
  • Honeywell HCA
  • Honeywell C300PM
  • Honeywell C200E

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.