CVE-2021-37206 Denial of service in SIPROTEC 5 relays with CPU variants CP050

High 7.5 Published Updated

An unauthenticated remote attacker can send specially crafted packets to SIPROTEC 5 relays, forcing a device restart and causing denial of service.

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-2021-37206?

CVE-2021-37206 is a high-severity denial of service vulnerability in Siemens SIPROTEC 5 relays with CPU variants CP050, published on 14 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability has been identified in SIPROTEC 5 relays with CPU variants CP050 (All versions < V8.80), SIPROTEC 5 relays with CPU variants CP100 (All versions < V8.80), SIPROTEC 5 relays with CPU variants CP300 (All versions < V8.80). Received webpackets are not properly processed. An unauthenticated remote attacker with access to any of the Ethernet interfaces could send specially crafted packets to force a restart of the target device.

Weakness: CWE-20

Which versions are affected by CVE-2021-37206?

It affects 3 products.

Products include Siemens Siprotec 5 With Cpu Variant Cp050, Siemens Siprotec 5 With Cpu Variant Cp100, Siemens Siprotec 5 With Cpu Variant Cp300.

How do I fix CVE-2021-37206?

No fix has been published for CVE-2021-37206 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-2021-37206 being exploited?

There is no known exploitation of CVE-2021-37206 in the wild and no public exploit code.

Sources

Also known as GHSA-m6hh-6w6m-5h5c.

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