CVE-2021-31882 Denial of service in Capital Embedded AR Classic 431-422

Medium 6.5 Published Updated

A missing length validation in the DHCP client allows attackers to cause a denial-of-service condition by sending malformed DHCP ACK packets.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Local or same network only
Victim action needed
Not needed
Fix
None listed

What is CVE-2021-31882?

CVE-2021-31882 is a medium-severity denial of service vulnerability in Siemens Capital Embedded AR Classic 431-422, published on 9 Nov 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303). The DHCP client application does not validate the length of the Domain Name Server IP option(s) (0x06) when processing DHCP ACK packets. This may lead to Denial-of-Service conditions. (FSMD-2021-0011)

Weakness: CWE-119

Which versions are affected by CVE-2021-31882?

It affects 10 products.

Products include Siemens Apogee Modular Building Controller Firmware, Siemens Apogee Modular Equiment Controller Firmware, Siemens Apogee Pxc Compact Firmware, Siemens Apogee Pxc Modular Firmware, Siemens Capital Vstar, Siemens Nucleus Net and 4 more.

How do I fix CVE-2021-31882?

No fix has been published for CVE-2021-31882 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-2021-31882 being exploited?

There is no known exploitation of CVE-2021-31882 in the wild and no public exploit code.

Sources

Also known as GHSA-w2w7-g4vg-h87m.

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