CVE-2021-34570 Phoenix Contact: DoS for PLCnext Control devices in versions prior to 2021.0.5 LTS

High 7.5 Published 27 Sep 2021 Updated 16 Sep 2024

Attackers can cause denial of service on Phoenix Contact PLCnext Control devices by sending specially crafted JSON requests.

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-2021-34570?

CVE-2021-34570 is a high-severity denial of service vulnerability in Phoenix Contact AXC F, published on 27 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Multiple Phoenix Contact PLCnext control devices in versions prior to 2021.0.5 LTS are prone to a DoS attack through special crafted JSON requests.

Weakness: CWE-20

Which versions are affected by CVE-2021-34570?

It affects 6 products.

Products include Phoenixcontact Axc F 1152 Firmware, Phoenixcontact Axc F 2152 Firmware, Phoenixcontact Axc F 2152 Starterkit Firmware, Phoenixcontact Axc F 3152 Firmware, Phoenixcontact Plcnext Technology Starterkit Firmware, Phoenixcontact Rfc 4072s Firmware.

How do I fix CVE-2021-34570?

No fix has been published for CVE-2021-34570 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-2021-34570 being exploited?

There is no known exploitation of CVE-2021-34570 in the wild and no public exploit code.

Sources

Also known as GHSA-5jgp-38vj-293v.