Stack-based Buffer OverflowWeakness · CWE-121

CVE-2023-43683

MEDIUM · 6.5 CVSS v3.1 Published 2025-08-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
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
An issue was discovered in Malwarebytes 4.6.14.326 and before 5.1.5.116 (and Nebula 2020-10-21 and later). A Stack buffer out-of-bounds access exists because of an integer underflow when handling newline characters.

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

A stack-based buffer out-of-bounds access vulnerability exists in Malwarebytes versions 4.6.14.326 and before 5.1.5.116 (and Nebula 2020-10-21 and later). The issue stems from an integer underflow when the software processes newline characters, allowing an attacker to potentially write beyond buffer boundaries on the stack. This could lead to code execution or denial of service.

MitigationUpdate Malwarebytes to version 5.1.5.116 or later (or Nebula post-2020-10-21) to patch the integer underflow vulnerability in newline character handling.

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

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
Low
Integrity
None
Availability
Low

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

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. Verify Malwarebytes installation
    Check if Malwarebytes is installed on the system by looking for its executable or service through system inventory tools or the installed programs list
    Affected if Malwarebytes is present on the system
  2. Identify the installed Malwarebytes version
    Locate the installed version of Malwarebytes using the product's built-in version information (typically found in the UI under About/Help, or via command-line tools if available)
    Affected if The exact version cannot be determined or the product is found to be installed
  3. Compare desktop version to affected range
    Compare your installed version against the affected range: versions 4.6.14.326 and any version before 5.1.5.116 are vulnerable
    Affected if The installed version is 4.6.14.326 or any version below 5.1.5.116 (for the standalone/desktop product)
  4. Check Nebula version if applicable
    If using Malwarebytes Nebula (cloud-managed endpoint protection), identify the Nebula agent or console version
    Affected if The Nebula version is from 2020-10-21 or later (and has not been updated to the patched release)

You are affected if Malwarebytes (standalone or Nebula) is installed and the detected version falls within 4.6.14.326 and before 5.1.5.116, or is a Nebula version from 2020-10-21 onward that has not been patched.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Malwarebytes to version 5.1.5.116 or later (or Nebula post-2020-10-21) to patch the integer underflow vulnerability in newline character handling.

Recommended fix High confidence

Malwarebytes version 5.1.5.117 or later (or latest stable release)

  1. 1. Open the Malwarebytes application on the affected system
  2. 2. Navigate to the Settings or About section
  3. 3. Check the current version number to confirm it is 5.1.5.116 or earlier, or 4.6.14.326 or earlier
  4. 4. Download the latest version of Malwarebytes from the official website (www.malwarebytes.com)
  5. 5. Run the installer and follow the prompts to upgrade to the latest version
  6. 6. Restart the system if prompted
  7. 7. Verify the installed version is newer than 5.1.5.116
Caveat Standard upgrade - ensure compatibility with your operating system before upgrading

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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Scan for this in your stack

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dbcve dependency scanner

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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-2023-43683 in production — separate from our analysis above.

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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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  • No spam, self-promotion, credentials, or personal data