CVE-2020-27339
MediumCVSS 6.7Exploitation Probability (EPSS)
Low risk24th percentile - higher than 24% of all known CVEs
Summary
In InsydeH2O 5.x, certain SMM drivers did not correctly validate CommBuffer and CommBufferSize parameters, allowing callers to corrupt firmware or OS memory. Affected drivers include AhciBusDxe, IdeBusDxe, NvmExpressDxe, SdHostDriverDxe, and SdMmcDeviceDxe.
Risk Assessment
The vulnerability may allow an attacker with SMM access to compromise memory integrity, potentially leading to system takeover.
Recommendation
Update firmware to patched versions (05.16.25, 05.26.25, 05.35.25, 05.43.25, 05.51.25) for the respective kernels.
Original NVD description (English source)
In the kernel in Insyde InsydeH2O 5.x, certain SMM drivers did not correctly validate the CommBuffer and CommBufferSize parameters, allowing callers to corrupt either the firmware or the OS memory. The fixed versions for this issue in the AhciBusDxe, IdeBusDxe, NvmExpressDxe, SdHostDriverDxe, and SdMmcDeviceDxe drivers are 05.16.25, 05.26.25, 05.35.25, 05.43.25, and 05.51.25 (for Kernel 5.1 through 5.5).