MELSEC iQ-F Series FX5U-32MT/ES: Missing Authentication for Critical Functionality
CVE-2025-7405 is a high-severity missing authentication for critical functionality vulnerability in MELSEC iQ-F Series FX5U-32MT/ES from Mitsubishi Electric, with a CVSS 3.1 base score of 7.3 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: 1.060 and later. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.48% 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
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by CNA (yd.MitsubishiElectric.co.jp).
Official description
Missing Authentication for Critical Function vulnerability in Mitsubishi Electric Corporation MELSEC iQ-F Series CPU module allows a remote unauthenticated attacker to read or write the device values of the product and stop the operation of the programs, since MODBUS/TCP in the products does not have authentication features.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Authentication for Critical Functionality
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
- When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data.
More Missing Authentication for Critical Functionality vulnerabilities (CWE-306)
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
- 7.5 High severity
- 9.1 Critical severity
- 8.1 High severity
- 7.5 High severity
- 9.1 Critical severity
Recent Missing Authentication for Critical Functionality vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 9.0 Critical severity
- 9.0 Critical severity
- 9.0 Critical severity
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