dbcve.org
Linkit Software Development KitApplication · Mediatek

CVE-2021-30636

CRITICAL · 9.8 CVSS v3.1 Published 2022-01-24
Fix available
A fix is available. Upgrade to 4.6.1 or later.
See remediation →
100/100
Remediation priority · Urgent
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 MediaTek LinkIt SDK before 4.6.1, there is a possible memory corruption due to an integer overflow during mishandled memory allocation by pvPortCalloc and pvPortRealloc.

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 · moderate confidence

Integer overflow in pvPortCalloc and pvPortRealloc memory allocation functions in MediaTek LinkIt SDK before v4.6.1 allows attackers to cause memory corruption via crafted allocation requests with oversized or manipulated size parameters.

MitigationUpgrade MediaTek LinkIt SDK to version 4.6.1 or later; audit all products using the SDK for exposure and implement input validation on allocation size parameters as defense-in-depth.

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
Linkit Software Development KitApplication
Affected:< 4.6.1

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Locate LinkIt SDK in your project
    Search your project directory for folders or files named 'LinkIt', 'mtk', or 'mediatek'. Check build system files (Makefile, CMakeLists.txt, platformio.ini, arduino.json) for references to LinkIt or MTK SDK paths.
    Affected if No LinkIt SDK references are found and your product does not use MediaTek LinkIt hardware, then you are not affected.
  2. Find the SDK version identifier
    Look for a version file or string within the LinkIt SDK directory. Common locations: a 'version.h', 'sdk_version', 'VERSION', or 'RELEASE_NOTES' file in the SDK root or docs folder. Also check your build configuration or dependency manifest for a version declaration.
    Affected if The SDK version cannot be determined and the product uses LinkIt hardware, treat it as potentially vulnerable until version is confirmed.
  3. Compare installed version to vulnerable range
    If a version is found, compare it to the vulnerable threshold: any version lower than 4.6.1 is affected. Extract the version number from the SDK files or build metadata and note whether it precedes v4.6.1.
    Affected if Installed version is below 4.6.1 (e.g., 4.5.0, 4.4.x, or any pre-4.6.1 release).
  4. Check for usage of pvPortCalloc or pvPortRealloc
    Search your project source code (.c, .cpp files) for calls to pvPortCalloc or pvPortRealloc functions. These are the vulnerable allocation functions. Review the firmware or application code that performs dynamic memory allocation.
    Affected if Your code uses pvPortCalloc or pvPortRealloc and the SDK version is below 4.6.1, the integer overflow condition can be triggered.

Your environment is affected if your product uses MediaTek LinkIt SDK with a version lower than 4.6.1 and your code calls pvPortCalloc or pvPortRealloc with attacker-controlled size parameters.

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.

dbcve · scoped
Upgrade available Upgrade to 4.6.1 or later
Fixed in 4.6.1
Interim mitigation

Upgrade MediaTek LinkIt SDK to version 4.6.1 or later; audit all products using the SDK for exposure and implement input validation on allocation size parameters as defense-in-depth.

Recommended fix High confidence

LinkIt SDK 4.6.1

  1. 1. Identify the current version of LinkIt SDK being used in your project by checking the SDK version file or build configuration
  2. 2. Obtain LinkIt SDK version 4.6.1 or later from the official MediaTek or LinkIt developer resources
  3. 3. Back up your existing project files and configurations
  4. 4. Replace the existing LinkIt SDK installation with the new version 4.6.1
  5. 5. Update any project references or include paths that point to the old SDK location
  6. 6. Clean and rebuild your project to ensure all components are compiled against the updated SDK
  7. 7. Perform thorough testing of your application, particularly focusing on memory allocation and dynamic memory operations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linkit Software Development Kit Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing24.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,520
Get the upgrade done

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Scan for this in your stack

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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-2021-30636 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data