CVE-2020-5953 Privilege escalation in n/a

High 7.5 Published 3 Feb 2022 Updated 11 Aug 2026

Attackers can execute code in System Management Mode by exploiting a pointer dereference in the InsydeH2O UEFI firmware, escalating privileges from ring 0 to ring -2.

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

What is CVE-2020-5953?

CVE-2020-5953 is a high-severity vulnerability in Insyde Insydeh2o, published on 3 Feb 2022. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A vulnerability exists in System Management Interrupt (SWSMI) handler of InsydeH2O UEFI Firmware code located in SWSMI handler that dereferences gRT (EFI_RUNTIME_SERVICES) pointer to call a GetVariable service, which is located outside of SMRAM. This can result in code execution in SMM (escalating privilege from ring 0 to ring -2).

Which versions are affected by CVE-2020-5953?

It affects 17 products.

Products include Insyde Insydeh2o, Siemens Ruggedcom Ape1808 Firmware, Siemens Simatic Field Pg M5 Firmware, Siemens Simatic Field Pg M6 Firmware, Siemens Simatic Ipc127e Firmware, Siemens Simatic Ipc227g Firmware and 11 more.

How do I fix CVE-2020-5953?

No fix has been published for CVE-2020-5953 yet. Limit exposure of the affected software until one is available.

Is CVE-2020-5953 being exploited?

There is no known exploitation of CVE-2020-5953 in the wild and no public exploit code.

All Insyde Insydeh2o vulnerabilities

Sources

Also known as GHSA-f8pw-77pg-8gv6.