Security readout for executives and security teams
Plain-English summary
CVE-2021-46795 is an AMD firmware-related issue where a compromised BIOS could cause AMD's trusted execution environment software to read outside expected memory. The documented impact is denial of service, not data theft or code execution. Business urgency is moderate because exploitation needs local access, high complexity, and BIOS compromise.
Executive priority
Treat this as a planned firmware-risk item, not an emergency remote-exploitation event. Prioritize validation and vendor firmware tracking for Ryzen 5000 fleets, especially business-critical endpoints or systems with strong availability requirements.
Technical view
The issue is a CWE-367 TOCTOU flaw in AMD AGESA affecting various Ryzen 5000 Series configurations. With a compromised BIOS, an attacker may trigger an out-of-bounds read by the TEE OS, potentially causing availability impact. CVSS is 4.7: local attack vector, high complexity, low privileges, no user interaction, availability high.
Likely exposure
Exposure is most likely on systems using affected AMD Ryzen 5000 Series firmware/AGESA versions. The supplied data lists Ryzen 3000 Series as unaffected. Exact affected BIOS or AGESA revisions are not included in the bundle, so exposure must be confirmed against AMD and OEM firmware guidance.
Exploitation context
The supplied sources do not show active exploitation, and the CVE is not marked KEV. The described scenario requires local access, low privileges, high attack complexity, and a compromised BIOS, making broad remote exploitation unlikely based on the available evidence.
Researcher notes
Evidence is limited to the CVE metadata and AMD bulletin reference. The bundle identifies TOCTOU, compromised BIOS precondition, AGESA package context, and denial-of-service impact, but does not provide exact vulnerable firmware revisions, proof of exploitation, or detailed remediation versions.
Mitigation direction
- Check AMD-SB-1031 and OEM advisories for affected BIOS or AGESA versions.
- Apply vendor-provided BIOS or firmware updates when they are identified for affected systems.
- Prioritize systems where downtime or trusted execution failures would create business impact.
- Restrict firmware modification paths and review BIOS integrity controls.
- Track remediation through standard endpoint and asset inventory processes.
Validation and detection
- Inventory AMD Ryzen 5000 systems and record BIOS, firmware, and AGESA versions.
- Compare collected versions with AMD-SB-1031 and device vendor advisories.
- Confirm Ryzen 3000 systems are not treated as affected from this source bundle.
- Review firmware change history for unexpected BIOS modifications.
- Document systems awaiting OEM guidance where fixed versions are unclear.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-367: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-46795 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H13.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.7MediumVector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-1031CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Time-of-check Time-of-use (TOCTOU) Race Condition
Time-of-check Time-of-use (TOCTOU) Race Condition represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.