CVE-2021-40365 Denial of service in SIMATIC Drive Controller CPU 1504D TF

High 7.5 Published 13 Dec 2022 Updated 21 Apr 2025

Attackers can cause denial of service on Siemens SIMATIC devices by sending crafted packets to port 102/tcp.

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-2021-40365?

CVE-2021-40365 is a high-severity denial of service vulnerability in Siemens SIMATIC Drive Controller CPU 1504D TF, published on 13 Dec 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Affected devices don't process correctly certain special crafted packets sent to port 102/tcp, which could allow an attacker to cause a denial of service in the device.

Weakness: CWE-20

Which versions are affected by CVE-2021-40365?

It affects 96 products.

Products include Siemens Simatic Et 200 Sp Open Controller Cpu 1515sp Pc Firmware, Siemens Simatic S7-1200 Cpu 1211c Firmware, Siemens Simatic S7-1200 Cpu 1212c Firmware, Siemens Simatic S7-1200 Cpu 1212fc Firmware, Siemens Simatic S7-1200 Cpu 1214 Fc Firmware, Siemens Simatic S7-1200 Cpu 1214c Firmware and 90 more.

How do I fix CVE-2021-40365?

No fix has been published for CVE-2021-40365 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-2021-40365 being exploited?

There is no known exploitation of CVE-2021-40365 in the wild and no public exploit code.

Sources

Also known as GHSA-6x86-2ph3-crc4.