Security readout for executives and security teams
Plain-English summary
This AMD firmware issue can let an attacker using a malicious bootloader consume Secure Processor SysHub resources and cause denial of service. The business impact is availability loss on affected AMD systems, not data theft based on the provided sources.
Executive priority
Treat this as a high-priority firmware availability risk for affected AMD fleets, especially servers, workstations, and business-critical desktops. Prioritize inventory and vendor firmware confirmation before emergency action, because the provided sources do not show active exploitation.
Technical view
CVE-2021-46755 is an ASP bootloader cleanup flaw: certain SysHub mappings are not unmapped on error paths. With a malicious bootloader, resources may be exhausted, causing potential denial of service. CVSS 3.1 score is 7.5 high with availability impact only.
Likely exposure
Exposure is most relevant to systems using the listed AMD Ryzen and Threadripper processor families with affected AGESA firmware. The bundle lists versions as various and does not provide exact vulnerable or fixed firmware revisions.
Exploitation context
CISA KEV status is false, and the supplied sources do not claim active exploitation. The description requires an attacker with a malicious bootloader; practical exploitability depends on platform boot controls and firmware state.
Researcher notes
The CVSS vector shows AV:N, but the vulnerability description specifically references an attacker with a malicious bootloader. Sources do not clarify this mismatch or provide exploit indicators, fixed AGESA versions, or detailed mitigation mechanics.
Mitigation direction
- Review AMD-SB-4001 and applicable OEM BIOS or UEFI guidance.
- Inventory systems using the listed AMD Ryzen and Threadripper processor families.
- Update platform firmware when AMD or the system vendor provides an applicable AGESA fix.
- Maintain Secure Boot and bootloader integrity controls where supported.
- Track vendor advisories for exact fixed firmware versions.
Validation and detection
- Record CPU model, motherboard or system model, BIOS version, and AGESA version.
- Compare firmware details against AMD-SB-4001 and OEM security advisories.
- Confirm updated firmware is installed after remediation.
- Check boot integrity settings are enabled where operationally feasible.
- Document systems where vendor guidance or fixed versions are unavailable.
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.
CVE-2021-46755 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.