VulnerabilityPublished 10 Jul 2025Updated 4 Aug 2025

CVE-2025-2520: Honeywell C300 PCNT02 · Use of Uninitialized Variable

Affects Honeywell C300 PCNT02Source CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 36% 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:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Honeywell C300 PCNT02	Affected =520.1 =530	Fixed in–

AI-suggested

Immediate application of Honeywell's recommended updates to Experion PKS versions 520.2 TCU9 HF1 or 530.1 TCU3 HF1 is essential to remediate the vulnerability.
Implement network segmentation to isolate Experion PKS components from general enterprise networks and limit exposure to untrusted networks.
Employ strict firewall rules and intrusion detection/prevention systems (IDS/IPS) to monitor and block suspicious traffic targeting EPA communications.
Conduct regular vulnerability assessments and penetration testing focused on ICS environments to detect similar issues proactively.
Establish robust incident response plans tailored for ICS disruptions, including procedures for rapid recovery from DoS conditions.
Maintain up-to-date asset inventories and software version tracking to ensure timely patch management.
Engage with Honeywell support and security advisories to stay informed about any emerging threats or additional patches related to this vulnerability.

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.

Impact

For European organizations, especially those operating in critical infrastructure sectors such as energy, manufacturing, and utilities, this vulnerability poses a significant risk. Honeywell Experion PKS is widely used in industrial control systems across Europe, and a denial of service attack could disrupt operational continuity, leading to production downtime, safety risks, and financial losses. The DoS condition could halt communication channels within the control system, potentially causing cascading failures or forcing manual intervention. While the vulnerability does not directly compromise data confidentiality or integrity, the availability impact on critical industrial processes can have severe operational and safety consequences. Given the increasing targeting of ICS environments by threat actors, European organizations must prioritize patching to maintain resilience and comply with regulatory requirements for critical infrastructure protection.

CWE-457Use of Uninitialized Variable (opens in a new tab)
Variant weaknessLikelihood of exploit: High
The code uses a variable that has not been initialized, leading to unpredictable or unintended results.
Implementation · Attack Surface Reduction
Ensure that critical variables are initialized before first use.
Build and Compilation · Compilation or Build Hardening
Most compilers will complain about the use of uninitialized variables if warnings are turned on.
Implementation · Operation
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.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

process.honeywell.com (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Aug 2025, 00:36 UTC

WeaknessesCWE-457

Technical details

References

Community reviews

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