Security readout for executives and security teams
Plain-English summary
This is a firmware-level AMD issue in how the platform security processor handles APCB data inside a BIOS image. A successful attacker could potentially run arbitrary code, but the stated prerequisites are substantial: BIOS image modification plus signing capability.
Executive priority
Treat this as high priority where affected AMD systems support sensitive workloads. The exploit path is difficult, but firmware compromise can undermine operating-system controls and recovery assumptions.
Technical view
CVE-2021-26344 is a CWE-787 out-of-bounds write while processing the AMD PSP1 Configuration Block. The CVSS 3.1 score is 7.2 with local access, high complexity, high privileges, user interaction, changed scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most relevant to organizations operating listed AMD EPYC, Ryzen, Threadripper, and Athlon platforms with affected firmware. This is not described as a remotely reachable network service issue.
Exploitation context
The bundle does not show KEV listing or active exploitation. Sources describe a constrained attack path requiring access to modify a BIOS image and sign the resulting image.
Researcher notes
Evidence is limited to the CVE record, CVE List data, and AMD advisory reference. The affected list includes broad “various” entries, so exact exposure depends on OEM firmware lineage and platform-specific advisory mapping.
Mitigation direction
- Review AMD SB-3003 and relevant OEM firmware advisories for affected platforms.
- Update BIOS or UEFI firmware only through trusted OEM or vendor channels.
- Prioritize servers, high-value workstations, and managed endpoints using listed AMD platforms.
- Protect firmware signing, update workflows, and administrator access paths.
- Check vendor guidance before assuming a specific fixed version.
Validation and detection
- Inventory systems using the affected AMD processor families.
- Record current BIOS, UEFI, and AGESA or PI firmware versions.
- Compare platform firmware against AMD SB-3003 and OEM advisories.
- Verify firmware update provenance and signing controls.
- Track remediation status for systems awaiting OEM firmware availability.
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-787: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-26344 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
- 7.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:C/C:H/I:H/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:H/UI:R/S:C/C:H/I:H/A:H0.66Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.2HighVector: CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3003.htmlCVE 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 Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.