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Armv8 M FirmwareOperating system · Arm

CVE-2020-16273

HIGH · 7.8 CVSS v3.1 Published 2020-11-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In Arm software implementing the Armv8-M processors (all versions), the stack selection mechanism could be influenced by a stack-underflow attack in v8-M TrustZone based processors. An attacker can cause a change to the stack pointer used by the Secure World from a non-secure application if the stack is not initialized. This vulnerability affects only the software that is based on Armv8-M processors with the Security Extension.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In Armv8-M processors with Security Extension (TrustZone), an uninitialized stack in non-secure applications can be exploited via stack-underflow to manipulate the stack selection mechanism, allowing an attacker to change the Secure World stack pointer from a non-secure context.

MitigationEnsure proper initialization of stack pointers for both Secure and Non-Secure states before entering TrustZone contexts, and validate stack pointer values on context switches.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Armv8 M FirmwareOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the processor architecture
    Check system documentation, device specifications, or use commands like 'cat /proc/cpuinfo' on Linux-based embedded systems to verify the processor is Armv8-M architecture
    Affected if The system does not use an Armv8-M processor, then this CVE does not apply
  2. Confirm TrustZone/Security Extension is enabled
    Check the processor's security configuration registers (e.g., ARM SCTLR or similar firmware-provided indicators) or review platform documentation for TrustZone enablement status
    Affected if TrustZone/Security Extension is disabled, the specific attack vector via non-secure stack manipulation does not apply
  3. Determine the firmware version
    Query the firmware version through vendor-specific interfaces, boot logs, or by accessing firmware identification registers/metadata (often via debug probes or platform-specific tools like 'fw_printenv' or vendor SDK utilities)
    Affected if The firmware version cannot be determined or is older than patched versions provided by the silicon/firmware vendor for Armv8-M TrustZone implementations
  4. Inspect stack initialization code
    If firmware source or binary analysis is possible, examine the TrustZone entry/exit code paths for proper initialization of both Secure and Non-Secure stack pointers before context switches. Look for stack pointer initialization in secure gateway or transition handler routines
    Affected if The firmware lacks proper stack pointer initialization in TrustZone transition handlers, leaving stack underflow conditions exploitable from non-secure context

A defender is affected if they run Armv8-M firmware with TrustZone enabled and the firmware does not properly initialize stack pointers before TrustZone context transitions, which can be confirmed by vendor firmware version or code analysis.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Ensure proper initialization of stack pointers for both Secure and Non-Secure states before entering TrustZone contexts, and validate stack pointer values on context switches.

Fix this in Armv8 M Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-16273 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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