Processor vulnerability
CVE-2023-20555
An SMM module of AGESA let an attacker set or clear a bit at an address of their choosing in SMM memory, which can lead to code execution in SMM.
- Name
- CpmDisplayFeatureSmm bit overwrite
- Vulnerability
- AMD AGESA, SMM and BIOS firmware
- Kind
- Firmware
- CVE published
- 2023-08-08 CVE record
- Advisories
- AMD-SB-4003
CpmDisplayFeatureSmm is an SMM module of AMD’s AGESA firmware.
Binarly’s efiXplorer team found that it did not validate a pointer
it takes from outside SMM, so an attacker could overwrite a single
bit at an address of their choosing in SMM memory and so corrupt
SMM. AMD fixed it in client AGESA releases of February and March
2023 and in the embedded ones later that year; the Threadripper
lines are not affected.What the sources say of each microarchitecture.
Affected processors
5 of the 5 microarchitectures listed are affected in all or some of their models.
| Microarchitecture | Status | Detail | Source |
|---|---|---|---|
| Zen | Affected | Athlon 3000 mobile (Dali, Pollock), Ryzen Embedded R1000 and V1000 | amd.com |
| Zen+ | Affected | Ryzen Embedded R2000 | amd.com |
| Zen 2 | Affected | Ryzen 3000 desktop (Matisse), Ryzen 4000 (Renoir), Ryzen 5000 mobile (Lucienne), Ryzen 7020 (Mendocino), Ryzen Embedded V2000 | amd.com |
| Zen 3 | Affected | Ryzen 5000 (Vermeer, Cezanne), Ryzen 6000 (Rembrandt), Ryzen 7030 (Barcelo), Ryzen Embedded 5000 and V3000 | amd.com |
| Zen 4 | Affected | Ryzen 7000 desktop (Raphael) | amd.com |
Mitigations
- Firmware: AGESA ComboAM4 PI 1.0.0.A, ComboAM4v2 PI 1.2.0.A, ComboAM5 1.0.0.6 and the mobile and embedded PI versions the bulletin lists, from 2023. Source.
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