LiveActive security incident?Get immediate response
CVE Record

CVE-2021-26370: Improper validation of destination address in SVC_LOAD_FW_IMAGE_BY_INSTANCE and SVC_LOAD_BINARY_BY_ATTRIB i...

Improper validation of destination address in SVC_LOAD_FW_IMAGE_BY_INSTANCE and SVC_LOAD_BINARY_BY_ATTRIB in a malicious UApp or ABL may allow an attacker to overwrite arbitrary bootloader memory with SPI ROM contents resulting in a loss of integrity and availability.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-26370 is a firmware/bootloader integrity issue affecting 2nd and 3rd Gen AMD EPYC systems. A malicious UApp or ABL could cause bootloader memory to be overwritten with SPI ROM contents, potentially disrupting availability or trust in the boot process.

Executive priority

Treat this as a platform firmware risk review. There is no provided evidence of active exploitation, but the potential impact is serious because bootloader integrity and server availability are involved. Prioritize critical EPYC infrastructure and verify OEM remediation status.

Technical view

The flaw is improper destination address validation in SVC_LOAD_FW_IMAGE_BY_INSTANCE and SVC_LOAD_BINARY_BY_ATTRIB. The published description says a malicious UApp or ABL may overwrite arbitrary bootloader memory with SPI ROM contents, causing integrity and availability impact.

Likely exposure

Exposure is limited to environments running 2nd Gen AMD EPYC or 3rd Gen AMD EPYC platforms. Versions are listed as unspecified, so teams must map hardware models, BIOS/firmware levels, and OEM guidance rather than relying on package scanners alone.

Exploitation context

The provided sources do not report active exploitation, public exploit availability, or inclusion in CISA KEV. The attack context appears local to malicious firmware-related components such as UApp or ABL, but the sources do not define prerequisite access in detail.

Researcher notes

Evidence is sparse: no CVSS vector, affected versions are unspecified, and remediation details are not included in the source bundle. The strongest grounded facts are the vulnerable AMD services, malicious UApp/ABL context, arbitrary bootloader memory overwrite, and affected EPYC generations.

Mitigation direction

  • Review AMD bulletin AMD-SB-1021 for official remediation guidance.
  • Check server OEM advisories for affected EPYC platform firmware updates.
  • Prioritize critical systems using 2nd or 3rd Gen AMD EPYC processors.
  • Apply only vendor-approved BIOS or platform firmware updates.
  • Maintain trusted firmware supply-chain and update controls.

Validation and detection

  • Inventory systems using 2nd and 3rd Gen AMD EPYC processors.
  • Record current BIOS, bootloader, and platform firmware versions.
  • Compare versions against AMD and OEM advisory guidance.
  • Confirm firmware updates came from approved vendor channels.
  • Document systems where affected status remains unresolved.
Prepared
Confidence
medium
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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 · low confidence lookup

CWE-20: 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 lookup
cve · low confidence lookup

CVE-2021-26370 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AMD2nd Gen AMD EPYC™unspecifiedListed
AMD3rd Gen AMD EPYC™unspecifiedListed
Weakness

CWE details

CWE-20

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.