CVE-2021-20599
Authorization bypass through user-controlled key vulnerability in MELSEC iQ-R series Safety CPU...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2021-20599- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-319
- Updated
- 2026-11-02
EUVDEUVD-2021-8017
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.
- Record
EUVD-2021-8017- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-vf46-vqq9-hg36
Authorization bypass through user-controlled key vulnerability in MELSEC iQ-R series Safety CPU...
Authorization bypass through user-controlled key vulnerability in MELSEC iQ-R series Safety CPU R08/16/32/120SFCPU all versions and MELSEC iQ-R series SIL2 Process CPU R08/16/32/120PSFCPU all versions allows an remote unauthenticated attacker to login to a target CPU module by obtaining credentials other than password.
- Record
GHSA-vf46-vqq9-hg36- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Weakness
- CWE-319, CWE-639, CWE-863
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-20599- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:P/I:N/A:N - Weakness
- CWE-319, CWE-639
- Updated
- 2026-11-02
Affected products
- mitsubishi electric corporation melsec iq-r series safety cpu r08sfcpu
- mitsubishi electric corporation melsec iq-r series safety cpu r120sfcpu
- mitsubishi electric corporation melsec iq-r series safety cpu r16sfcpu
- mitsubishi electric corporation melsec iq-r series safety cpu r32sfcpu
- mitsubishi electric corporation melsec iq-r series sil2 process cpu r08psfcpu
- mitsubishi electric corporation melsec iq-r series sil2 process cpu r120psfcpu
- mitsubishi electric corporation melsec iq-r series sil2 process cpu r16psfcpu
- mitsubishi electric corporation melsec iq-r series sil2 process cpu r32psfcpu
- mitsubishielectric melsec iq-r08sfcpu
- mitsubishielectric r08psfcpu
- mitsubishielectric r08psfcpu firmware
- mitsubishielectric r08sfcpu firmware
Show 12 moreShow less
- mitsubishielectric r120psfcpu
- mitsubishielectric r120psfcpu firmware
- mitsubishielectric r120sfcpu
- mitsubishielectric r120sfcpu firmware
- mitsubishielectric r16psfcpu
- mitsubishielectric r16psfcpu firmware
- mitsubishielectric r16sfcpu
- mitsubishielectric r16sfcpu firmware
- mitsubishielectric r32psfcpu
- mitsubishielectric r32psfcpu firmware
- mitsubishielectric r32sfcpu
- mitsubishielectric r32sfcpu firmware
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-20599 is a critical vulnerability (CVSS 9.1) in Mitsubishi Electric Corporation Melsec Iq-r Series Safety Cpu R08sfcpu, published October 14, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.40%, the 72nd percentile. No source names a fixed version.