CVE-2011-20001 Denial of service in SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants)
Unauthenticated remote attackers can cause denial of service on Siemens SIMATIC S7-1200 CPUs by sending malformed HTTP traffic.
- 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-2011-20001?
CVE-2011-20001 is a high-severity denial of service vulnerability in Siemens SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants), published on 14 Oct 2025. 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 SIMATIC S7-1200 CPU V1 family (incl. SIPLUS variants) (All versions < V2.0.3), SIMATIC S7-1200 CPU V2 family (incl. SIPLUS variants) (All versions < V2.0.3). The web server interface of affected devices improperly processes incoming malformed HTTP traffic at high rate. This could allow an unauthenticated remote attacker to force the device entering the stop/defect state, thus creating a denial of service condition.
Weakness: CWE-20
Which versions are affected by CVE-2011-20001?
How do I fix CVE-2011-20001?
No fix has been published for CVE-2011-20001 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-2011-20001 being exploited?
There is no known exploitation of CVE-2011-20001 in the wild and no public exploit code.
Sources
Also known as GHSA-hfrj-93xv-cmrv.