CVE-2021-33720 Denial of service in SIPROTEC 5 relays with CPU variants CP050
Attackers can cause a denial-of-service condition in Siemens SIPROTEC 5 relays by sending specially crafted packets to port 4443/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-2021-33720?
CVE-2021-33720 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). Specially crafted packets sent to port 4443/tcp could cause a Denial-of-Service condition.
Weakness: CWE-120
Which versions are affected by CVE-2021-33720?
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-2021-33720?
No fix has been published for CVE-2021-33720 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-2021-33720 being exploited?
There is no known exploitation of CVE-2021-33720 in the wild and no public exploit code.
Other vulnerabilities in Siemens SIPROTEC 5 relays with CPU variants CP050
Sources
Also known as GHSA-h98r-cwxp-2m8m.