Security readout for executives and security teams
Plain-English summary
This high-severity AMD firmware issue could let an attacker who already controls SMM trigger unsafe reads inside the AMD Secure Processor, potentially causing denial of service. The business impact is platform instability on affected Ryzen systems. The sources do not show active exploitation or data theft.
Executive priority
Treat as a high-priority firmware governance item for affected AMD fleets, especially managed workstations and laptops. It does not currently justify emergency response on exploitation grounds, but firmware updates often require planning, reboots, and OEM coordination.
Technical view
CVE-2021-46765 is CWE-125 insufficient input validation in AMD ASP/AGESA. AMD describes an attacker with compromised SMM inducing out-of-bounds memory reads within ASP, potentially leading to denial of service. CVSS 3.1 is 7.5 with availability-only impact.
Likely exposure
Exposure is likely limited to systems using the AMD Ryzen processor families and AGESA firmware lines identified in AMD-SB-4001, including listed Cezanne, Renoir, Lucienne, and Rembrandt platforms. Confirm through hardware inventory, BIOS vendor data, and AMD/OEM firmware guidance.
Exploitation context
The provided sources do not identify public exploitation, and the CVE is not marked KEV. AMD’s description includes an important precondition: the attacker has compromised SMM before affecting ASP. That suggests this is more likely a post-compromise platform reliability risk than an initial access vulnerability.
Researcher notes
Evidence is limited to AMD/CVE descriptions. The key technical detail is an ASP out-of-bounds read reachable after SMM compromise, with denial-of-service impact. Avoid assuming confidentiality impact, universal Ryzen exposure, or a standalone remote exploit path from the available sources.
Mitigation direction
- Review AMD-SB-4001 and OEM BIOS guidance for affected platforms.
- Update BIOS or AGESA firmware where the vendor provides a relevant fix.
- Prioritize laptops and desktops using listed Ryzen processor families.
- Monitor AMD and OEM advisories for revised affected-version details.
Validation and detection
- Inventory endpoints by AMD processor family and BIOS/AGESA version.
- Map models against AMD-SB-4001 and OEM security advisories.
- Confirm whether firmware management tools report current BIOS levels.
- Track remediation status separately from operating system patch compliance.
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-125: 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-2021-46765 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/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-4001CVE reference · vendor-advisory
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.