MELSEC iQ-F Series FX5U-32MT/ES: Cleartext Transmission of Sensitive Information
CVE-2025-7731 is a high-severity cleartext transmission of sensitive information vulnerability in MELSEC iQ-F Series FX5U-32MT/ES from Mitsubishi Electric, 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 MELSEC iQ-F Series FX5U-32MT/ES versions: All versions. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.35% 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 MELSEC iQ-F Series FX5U-32MT/ES you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on mitsubishielectric.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. 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
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA (yd.MitsubishiElectric.co.jp).
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Cleartext Transmission of Sensitive Information
The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.
How developers prevent this class of flaw
- Before transmitting, encrypt the data using reliable, confidentiality-protecting cryptographic protocols.
- When using web applications with SSL, use SSL for the entire session from login to logout, not just for the initial login page.
- 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.
More Cleartext Transmission of Sensitive Information vulnerabilities (CWE-319)
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 vulnerabilities in MELSEC iQ-F Series FX5U-32MT/ES
- 7.3 High severity
- 9.1 Critical severity
- 8.1 High severity
- 7.5 High severity
- 9.1 Critical severity
Recent Cleartext Transmission of Sensitive Information vulnerabilities
- 8.5 High severity
- 7.5 High severity
- 7.3 High severity
- 7.5 High severity
- 8.7 High severity
- 10.0 Critical severity
Spotted an error? Tell us.