CVE-2018-7856 Denial of service in Modicon M580 Modicon M340 Modicon Quantum Modicon Premium

High 7.5 Published 22 May 2019 Updated 5 Aug 2024

Attackers can cause denial of service on Schneider Electric Modicon PLCs by writing invalid memory blocks via Modbus.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2018-7856?

CVE-2018-7856 is a high-severity denial of service vulnerability in Modicon M580 Modicon M340 Modicon Quantum Modicon Premium, published on 22 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A CWE-248: Uncaught Exception vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause a possible denial of Service when writing invalid memory blocks to the controller over Modbus.

Weakness: CWE-754

Which versions are affected by CVE-2018-7856?

It affects 4 products.

Products include Schneider-Electric Modicon M340 Firmware, Schneider-Electric Modicon M580 Firmware, Schneider-Electric Modicon Premium Firmware, Schneider-Electric Modicon Quantum Firmware.

How do I fix CVE-2018-7856?

No fix has been published for CVE-2018-7856 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2018-7856 being exploited?

There is no known exploitation of CVE-2018-7856 in the wild and no public exploit code.

Sources

Also known as GHSA-g8pp-m4fh-wjg4.