C300 PCNT02: Use of Uninitialized Variable
CVE-2025-2520 is a high-severity use of uninitialized variable vulnerability in C300 PCNT02 from Honeywell, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected C300 PCNT02 versions: 520.1 through 520.2 TCU9; 530 through 530 TCU3. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of C300 PCNT02 you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Honeywell | C300 PCNT02 | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | EHB | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | EHPM | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | ELMM | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | Classic ENIM | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | ETN | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | FIM4 | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | FIM8 | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | PGM | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
| Honeywell | RFIM | 520.1 through 520.2 TCU9; 530 through 530 TCU3 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (honeywell.com).
Official description
The Honeywell Experion PKS contains an Uninitialized Variable in the common Epic Platform Analyzer (EPA) communications. An attacker could potentially exploit this vulnerability, leading to a Communication Channel Manipulation, which results in a dereferencing of an uninitialized pointer leading to a denial of service. Honeywell recommends updating to the most recent version of Honeywell Experion PKS: 520.2 TCU9 HF1and 530.1 TCU3 HF1. The affected Experion PKS products are C300 PCNT02, EHB, EHPM, ELMM, Classic ENIM, ETN, FIM4, FIM8, PGM, and RFIM. The Experion PKS versions affected are from 520.1 through 520.2 TCU9 and from 530 through 530 TCU3.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Uninitialized Variable
The code uses a variable that has not been initialized, leading to unpredictable or unintended results.
How developers prevent this class of flaw
- Ensure that critical variables are initialized before first use.
- Most compilers will complain about the use of uninitialized variables if warnings are turned on.
- When using a language that does not require explicit declaration of variables, run or compile the software in a mode that reports undeclared or unknown variables. This may indicate the presence of a typographic error in the variable's name.
More Use of Uninitialized Variable vulnerabilities (CWE-457)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in C300 PCNT02
- 8.2 High severity
- 8.2 High severity
- 9.4 Critical severity
- 8.6 High severity
Recent Use of Uninitialized Variable vulnerabilities
- 8.6 High severity
- 8.8 High severity
- 7.7 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
Spotted an error? Tell us.