CVE-2025-7731VulnerabilityPublished 1 Sep 2025Updated 2 Sep 2025

CVE-2025-7731: Mitsubishi Electric MELSEC iQ-F Series FX5U-32MT/ES · Cleartext Transmission

Affects Mitsubishi Electric MELSEC iQ-F Series FX5U-32MT/ESSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% 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:H/I:N/A:N

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

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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 1 Sep 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 2026-10-25.

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 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
Mitsubishi Electric Corporation MELSEC iQ-F Series FX5U-32MT/ES	Affected *	Fixed in–

AI-suggested

1. Network Segmentation: Isolate MELSEC iQ-F Series PLCs on dedicated, secure industrial networks separated from corporate IT networks and the internet to reduce exposure to remote attackers. 2. Use of VPNs and Encrypted Channels: Implement secure communication tunnels (e.g., VPNs, IPsec) for any remote access to PLCs to prevent interception of cleartext credentials. 3. Monitoring and Intrusion Detection: Deploy network monitoring tools and anomaly detection systems tailored for industrial protocols to detect unauthorized SLMP traffic or suspicious commands. 4. Access Control: Restrict network access to PLCs using firewalls and access control lists, allowing only trusted management stations and operators. 5. Vendor Coordination: Engage with Mitsubishi Electric for firmware updates or patches addressing this vulnerability and apply them promptly once available. 6. Credential Management: Change default or factory credentials and implement strong, unique passwords for device access. 7. Incident Response Planning: Prepare response procedures for potential PLC compromise, including backup and recovery of control programs and rapid isolation of affected devices. These measures go beyond generic advice by focusing on network architecture, encrypted communications, and proactive monitoring specific to industrial control environments.

Description

Cleartext Transmission of Sensitive Information vulnerability in Mitsubishi Electric Corporation MELSEC iQ-F Series CPU module allows a remote unauthenticated attacker to obtain credential information by intercepting SLMP communication messages, and read or write the device values of the product and stop the operations of programs by using the obtained credential information.

Impact

For European organizations, especially those in manufacturing, energy, utilities, and critical infrastructure sectors, this vulnerability poses a significant risk. The MELSEC iQ-F Series PLCs are widely used in industrial automation across Europe. Exploitation could lead to unauthorized disclosure of credentials, enabling attackers to manipulate industrial processes remotely. This could result in production downtime, safety incidents, or damage to physical equipment. Confidentiality breaches may expose sensitive operational data, potentially affecting competitive advantage or regulatory compliance. Although no direct integrity or availability impact is indicated by the CVSS vector, the ability to stop program operations suggests potential for denial-of-service conditions or process sabotage. Given the increasing targeting of industrial control systems by cyber adversaries, European organizations operating these devices face heightened risk of espionage, sabotage, or ransomware attacks leveraging this vulnerability.

CWE-319Cleartext Transmission of Sensitive Information (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.
Architecture and Design
Before transmitting, encrypt the data using reliable, confidentiality-protecting cryptographic protocols.
Implementation
When using web applications with SSL, use SSL for the entire session from login to logout, not just for the initial login page.
Implementation
When designing hardware platforms, ensure that approved encryption algorithms (such as those recommended by NIST) protect paths from security critical data to trusted user applications.
OWASP Cheat Sheets
Transport Layer Protection (opens in a new tab)
TLS Cipher String (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
Cryptographic Storage (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.1 (opens in a new tab)
V9.2.2 (opens in a new tab)
V1.9.1 (opens in a new tab)
Attack patterns
Session Sidejacking (opens in a new tab)
Harvesting Information via API Event Monitoring (opens in a new tab)
Signature Spoofing by Mixing Signed and Unsigned Content (opens in a new tab)
Sniff Application Code (opens in a new tab)
Interception (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Sep 2025, 06:46 UTC

WeaknessesCWE-319

Technical details

References

Community reviews

Related threats