Public proof of conceptFix available

CVE-2022-40267

Q: Is CVE-2022-40267 actively exploited?

A proof-of-concept exploit exists for CVE-2022-40267, but active exploitation has not been confirmed at this time.

Q: What is the CVSS score for CVE-2022-40267?

CVE-2022-40267 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

A public proof of concept exists; no exploitation attested.

Published2023-01-20
Fixed in1.003
WeaknessCWE-335 · CWE-337

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Predictable Seed in Pseudo-Random Number Generator (PRNG) vulnerability in Mitsubishi Electric Corporation MELSEC iQ-F Series FX5U-xMy/z (x=32,64,80, y=T,R, z=ES,DS,ESS,DSS) with serial number 17X**** or later, and versions 1.280 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5U-xMy/z (x=32,64,80, y=T,R, z=ES,DS,ESS,DSS) with serial number 179**** and prior, and versions 1.074 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5UC-xMy/z (x=32,64,96, y=T, z=D,DSS)) with serial number 17X**** or later, and versions 1.280 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5UC-xMy/z (x=32,64,96, y=T, z=D,DSS)) with serial number 179**** and prior, and versions 1.074 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5UC-32MT/DS-TS versions 1.280 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5UC-32MT/DSS-TS versions 1.280 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5UJ-xMy/z (x=24,40,60, y=T,R, z=ES,ESS) versions 1.042 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5UJ-xMy/ES-A (x=24,40,60, y=T,R) versions 1.043 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5S-xMy/z (x=30,40,60,80, y=T,R, z=ES,ESS) versions 1.003 and prior, Mitsubishi Electric Corporation MELSEC iQ-F Series FX5UC-32MR/DS-TS versions 1.280 and prior, Mitsubishi Electric Corporation MELSEC iQ-R Series R00/01/02CPU versions 33 and prior, Mitsubishi Electric Corporation MELSEC iQ-R Series R04/08/16/32/120(EN)CPU versions 66 and prior allows a remote unauthenticated attacker to access the Web server function by guessing the random numbers used for authentication from several used random numbers.

Timeline

dates in UTC

2023-01-2008:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2022-40267?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2022-40267?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · CISA-ADP

Mitsubishielectric fx5s-30mr\/es firmwareversion to verify

Branch	Affected	Fixed in	Source
1.3	< 1.003	1.003	NVD
1.42	≤ 1.042	no fix published	CISA-ADP

Mitsubishielectric fx5s-30mt\/es firmwareversion to verify

Branch	Affected	Fixed in	Source
1.3	< 1.003	1.003	NVD
1.42	≤ 1.042	no fix published	CISA-ADP

Mitsubishielectric fx5s-30mt\/ess firmwareversion to verify

Branch	Affected	Fixed in	Source
1.3	< 1.003	1.003	NVD
1.42	≤ 1.042	no fix published	CISA-ADP

50 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-23-017-02 CISA10 known affected
Mitsubishi Electric MELSEC iQ-F, iQ-R Series
MELSEC iQ-F and iQ-R Series products: FX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS: Versions 1.280 and prior · MELSEC iQ-F and iQ-R Series products: FX5UC-xMy/z x=32,64,96 y=T, z=D,DSS: Versions 1.280 and prior · MELSEC iQ-F and iQ-R Series products: FX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS: Versions 1.074 and prior · +7 more

Full record on NVD

Fix

Update Mitsubishielectric fx5s-30mr\/es firmware to 1.003
Mitigation from the vendor CISA ICSA-23-017-02 · 10 productsMELSEC iQ-F Series with serial number 17X**** or later: FX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS: Update to v1.281 or later FX5UC-xMy/z x=32,64,96 y=T, z=D,DSS: Update to v1.281 or later
Mitigation from the vendor CISA ICSA-23-017-02 · 10 productsFX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS: Update to v1.281 or later
Mitigation from the vendor CISA ICSA-23-017-02 · 10 productsFX5UC-xMy/z x=32,64,96 y=T, z=D,DSS: Update to v1.281 or later
Mitigation from the vendor CISA ICSA-23-017-02 · 10 productsMELSEC iQ-F Series with serial number 179**** and prior: FX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS: Update to v1.075 or later FX5UC-xMy/z x=32,64,96 y=T, z=D,DSS: Update to v1.075 or later
Mitigation from the vendor CISA ICSA-23-017-02 · 10 productsFX5U-xMy/z x=32,64,80, y=T,R, z=ES,DS,ESS,DSS: Update to v1.075 or later
Mitigation from the vendor CISA ICSA-23-017-02 · 10 productsFX5UC-xMy/z x=32,64,96 y=T, z=D,DSS: Update to v1.075 or later

Advisories and patches

jvn.jpMitigation
www.cisa.govMitigation
www.mitsubishielectric.comMitigation · Vendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionpoc2024-08-01
OpenCVESSVC decisionpoc—
CNACVSS 3.15.9read 2026-10-23
NVDCVSS 3.19.1read 2026-10-23
CNAweakness (CWE)CWE-337read 2026-10-23
NVDweakness (CWE)CWE-335read 2026-10-23
FIRST EPSSEPSS score1.2 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Published: 2023-01-20
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2022-40267?

Is CVE-2022-40267 actively exploited?

A proof-of-concept exploit exists for CVE-2022-40267, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2022-40267?

CVE-2022-40267 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

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