Security readout for executives and security teams
Plain-English summary
This flaw affects specific Arm microcontroller cores where a non-secure exception handler may access part of a Secure context. For organizations using affected embedded devices, the business concern is leakage or alteration of data intended to be isolated by Arm’s security boundary.
Executive priority
Treat as high priority where affected Arm cores protect secrets, device identity, safety functions, or trusted firmware. Lower priority may be appropriate where the affected cores or Secure context features are not present.
Technical view
CVE-2021-35465 concerns incorrect handling of exceptions affecting the VLLDM instruction in certain Arm Cortex-M and Arm China STAR-MC1 configurations. A Non-secure handler may gain read or write access to part of a Secure context on listed core revisions before 2021-08-23.
Likely exposure
Exposure is most likely in embedded products, IoT devices, industrial systems, or firmware platforms using the affected core revisions: Cortex-M33 r0p0-r1p0, Cortex-M35P r0, Cortex-M55 r0p0-r1p0, or STAR-MC1 in STAR SE configuration.
Exploitation context
The provided sources do not state active exploitation, public exploit availability, or CISA KEV inclusion. The impact depends on affected hardware presence, Secure/Non-secure partitioning, exception handling, and deployed firmware behavior.
Researcher notes
Evidence is limited to the CVE description and Arm references. No CVSS, CWE, exploit status, or detailed mitigation text is present in the supplied bundle, so validation should focus on hardware revision, TrustZone usage, and vendor remediation guidance.
Mitigation direction
- Check Arm’s security update for product-specific remediation guidance.
- Confirm silicon vendor firmware, SDK, or errata updates for affected cores.
- Prioritize devices that rely on Secure context isolation for keys or sensitive state.
- Track downstream OEM advisories for embedded products using affected Arm cores.
Validation and detection
- Inventory devices and firmware platforms using affected Arm Cortex-M or STAR-MC1 cores.
- Verify core revision against the affected ranges listed by Arm and CVE sources.
- Determine whether the product uses Secure and Non-secure execution contexts.
- Review vendor errata, firmware release notes, and security advisories for remediation status.
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-2021-35465 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://developer.arm.com/support/arm-security-updatesCVE reference · x_refsource_MISC
- https://developer.arm.com/support/arm-security-updates/vlldm-instruction-security-vulnerabilityCVE reference · x_refsource_CONFIRM
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.