CVE-2023-3346: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in MITSUBSHI CNC Series a

This week

CRITICAL 9.8REMOTEMITIGATEMITIGATEMITIGATE

CVE-2023-3346 is a critical-severity flaw (CVSS 9.8) affecting c80 firmware, e70 firmware, e80 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in MITSUBSHI CNC Series allows a remote unauthenticated attacker to cause Denial of Service (DoS) condition and execute arbitrary code on the product by sending specially crafted packets. In addition, system reset is required for recovery.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.1% (top 18%)
CISA exploited list	No
Weakness	CWE-120
Published	2023-08-03
Last modified	2026-06-17

Publisher (CNA): Mitsubishi Electric Corporation · Vendor: mitsubishielectric

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-08-03 05:15 UTCPublished CVE record published
2026-06-17 06:13 UTCUpdated Record last modified

mitsubishielectric c80 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mitsubishielectric e70 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mitsubishielectric e80 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mitsubishielectric m70v firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mitsubishielectric m720vs firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

mitsubishielectric m720vs 15-type firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-3346?

c80 firmware: mitigate or apply the listed mitigation; e70 firmware: mitigate or apply the listed mitigation; e80 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-3346 being exploited?

CVE-2023-3346 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-3346 affect?

CVE-2023-3346 affects c80 firmware, e70 firmware, e80 firmware. Severity is critical (CVSS 9.8). Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in MITSUBSHI CNC Series allows a remote unauthenticated attacker to cause Denial of Service (DoS) condition and execute arbitrary code on the product by se

How urgent is CVE-2023-3346?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

References

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