Security readout for executives and security teams
Plain-English summary
This is a low-severity AMD platform firmware issue. An attacker would already need very high privileges, AMD signing-key access, and BIOS menu or UEFI shell access. If those conditions exist, protected memory regions could be mapped, which may weaken platform integrity.
Executive priority
Handle through normal firmware risk management, not emergency response, unless your environment has weak firmware access controls or sensitive AMD signing-key workflows.
Technical view
CVE-2021-26387 is CWE-863 insufficient access control in the AMD Secure Processor kernel. The CVSS 3.1 score is 3.9 with local access, high complexity, high privileges, changed scope, and limited integrity and availability impact. Affected products span multiple EPYC, Ryzen, Athlon, and Threadripper families.
Likely exposure
Exposure is most relevant to organizations operating affected AMD EPYC, Ryzen, Athlon, or Threadripper systems with vulnerable platform initialization or firmware versions. The practical attack path appears constrained by local, privileged, firmware-level access requirements.
Exploitation context
The provided bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires unusually strong prerequisites: privileged access, AMD signing keys, and BIOS menu or UEFI shell access.
Researcher notes
Evidence is limited to the CVE record and AMD advisory references. The affected list is broad, but exploitability is constrained by high privileges, local access, high complexity, and signing-key plus firmware-interface prerequisites.
Mitigation direction
- Review AMD SB-3003 and SB-5002 for vendor firmware guidance.
- Check OEM BIOS or UEFI update channels for affected systems.
- Restrict BIOS menu and UEFI shell access to trusted administrators.
- Protect firmware-signing material and related privileged workflows.
- Prioritize servers or workstations with affected AMD processor families.
Validation and detection
- Inventory AMD processor families across servers, desktops, and laptops.
- Record BIOS, UEFI, AGESA, or PI firmware versions where available.
- Compare inventory against affected products and versions in the CVE record.
- Confirm firmware access controls limit BIOS menu and UEFI shell use.
- Track AMD and OEM advisories for applicable remediation status.
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-863: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2021-26387 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
- Low
- CVSS
- 3.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:L/A:L
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:H/UI:N/S:C/C:N/I:L/A:L0.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
3.9LowVector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3003.htmlCVE reference · vendor-advisory
- https://www.amd.com/en/resources/product-security/bulletin/amd-sb-5002.htmlCVE 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.
Incorrect Authorization
Incorrect Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.