dbcve.org
MiwiApplication · Microchip

CVE-2021-37604

HIGH · 7.5 CVSS v3.1 Published 2021-08-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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 version 6.5 of Microchip MiWi software and all previous versions including legacy products, there is a possibility of frame counters being validated/updated prior to the message authentication. With this vulnerability in place, an attacker may increment the incoming frame counter values by injecting messages with a sufficiently large frame counter value and invalid payload. This results in denial of service/valid packets in the network. There is also a possibility of a replay attack in the stack.

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 Microchip MiWi protocol stack versions 6.5 and prior, frame counter validation and updates occur BEFORE message authentication is verified. This allows an attacker to inject messages with manipulated frame counters and invalid payloads, causing the receiver to increment its counter prematurely. This locks out legitimate frames (DoS) and enables replay attacks since authentication is not checked first.

MitigationReorder the security validation sequence to perform message authentication (MAC verification) BEFORE any frame counter validation or update operations. This ensures invalid/malicious frames are rejected before affecting the counter state.

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
MiwiApplication
Affected:= 6.5

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

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. Confirm MiWi protocol stack is in use
    Identify if your embedded system or application uses the Microchip MiWi wireless protocol stack for communication. Check project dependencies, library imports, or firmware documentation for 'MiWi' or 'MiWi protocol'.
    Affected if MiWi protocol stack is not present in the environment.
  2. Identify the MiWi library version
    Locate the MiWi library or source files in your project and check the version number. This may be in header files (e.g., MiWi.h), library manifest, or firmware documentation. Look for version strings mentioning '6.5' or earlier.
    Affected if The installed MiWi version is 6.5 or any version prior to 6.5.
  3. Verify security features are enabled
    Check if MiWi security/MAC (message authentication) is enabled in your configuration. Look for settings like SECURITY_ENABLED, MIWI_SECURITY, or similar security-related defines in your configuration files or stack initialization code.
    Affected if Security (MAC verification) is not enabled - the vulnerability only applies when authentication is used.
  4. Review security validation code order
    Examine the source code implementing the MiWi security validation sequence. Look for the functions that handle frame counter validation and MAC verification. Check if frame counter is validated or incremented BEFORE the MAC is verified.
    Affected if The code processes frame counter validation or updates before performing MAC (message authentication code) verification.
  5. Test behavioral response to crafted frames
    If source code is unavailable, send a test frame with a manipulated/invalid frame counter and observe the receiver behavior. A vulnerable implementation will increment its counter or reject the frame before checking MAC validity.
    Affected if The receiver increments its frame counter or enters a rejection state for frames with invalid counters without first validating the MAC.

A system is affected if it uses Microchip MiWi protocol stack version 6.5 or prior with security/MAC enabled, and the implementation validates or updates the frame counter before verifying message authentication.

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

Reorder the security validation sequence to perform message authentication (MAC verification) BEFORE any frame counter validation or update operations. This ensures invalid/malicious frames are rejected before affecting the counter state.

Fix this in Miwi Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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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-2021-37604 in production — separate from our analysis above.

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What this is

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What belongs here
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