Security readout for executives and security teams
Plain-English summary
This flaw affects AMD Secure Processor handling on listed 1st, 2nd, and 3rd Gen EPYC platforms. A local attacker with low privileges, through a compromised user application or ABL, could corrupt secure processor OS memory and potentially run arbitrary code.
Executive priority
Treat this as a high-priority firmware governance issue for EPYC server fleets, especially where local compromise could lead to broader platform trust concerns. It is not evidenced as actively exploited in the provided sources.
Technical view
CVE-2021-26398 is insufficient input validation in the SYS_KEY_DERIVE system call. The CVE maps to CWE-787 and has CVSS 7.8: local access, low complexity, low privileges, no user interaction, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most relevant to organizations running AMD 1st, 2nd, or 3rd Gen EPYC servers with affected AGESA firmware. The bundle lists versions only as various, so exact exposure depends on AMD and system-OEM firmware guidance.
Exploitation context
The source bundle does not show CISA KEV listing or public active exploitation evidence. Exploitation requires local low-privileged access and a compromised user application or ABL, reducing remote mass-exploitation likelihood but raising concern for shared or already-compromised servers.
Researcher notes
Key gaps are exact affected and fixed AGESA versions in the supplied bundle. Validation should focus on mapping hardware generations to OEM firmware advisories, not attempting proof-of-concept exploitation. The issue is local, privileged-context adjacent, and security-processor-impacting.
Mitigation direction
- Review AMD-SB-1032 and system-OEM advisories for affected firmware levels.
- Apply AMD or OEM firmware updates where guidance identifies this CVE.
- Prioritize EPYC servers hosting sensitive, multi-tenant, or high-trust workloads.
- Reduce local code execution paths on critical EPYC servers.
- Monitor AMD and OEM guidance for clarified fixed AGESA versions.
Validation and detection
- Inventory servers using AMD 1st, 2nd, or 3rd Gen EPYC processors.
- Record BIOS, firmware, and AGESA versions from vendor management tooling.
- Compare recorded versions against AMD-SB-1032 and OEM advisories.
- Confirm firmware update status after maintenance windows.
- Check vulnerability scanners for CVE-2021-26398 coverage and evidence.
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-2021-26398 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-1032CVE 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.