Schneider Electric · Modicon M340 Cpu · CVE-2021-22788
**Name of the Vulnerable Software and Affected Versions**
Modicon M340 CPUs versions prior to V3.40
Modicon M340 X80 Ethernet Communication Modules versions (all versions)
Modicon Premium Processors with integrated Ethernet versions (all versions)
Modicon Quantum Processors with Integrated Ethernet versions (all versions)
Modicon Quantum Communication Modules versions (all versions)
Modicon Premium Communication Modules versions (all versions)
**Description**
The issue is related to a buffer overflow in the software of programmable logic controllers. An attacker can exploit this by sending specially crafted HTTP requests, potentially causing a denial of service.
**Recommendations**
For Modicon M340 CPUs versions prior to V3.40, update to version V3.40 or later.
For Modicon M340 X80 Ethernet Communication Modules, restrict access to the web server until a patch is available.
For Modicon Premium Processors with integrated Ethernet, consider disabling the HTTP server functionality until a fix is provided.
For Modicon Quantum Processors with Integrated Ethernet, avoid using the vulnerable communication modules until an update is released.
For Modicon Quantum Communication Modules and Modicon Premium Communication Modules, limit network exposure to these modules until a patch is available.