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PatchSiren cyber security CVE debrief

CVE-2023-43686 Malwarebytes CVE debrief

CVE-2023-43686 is a medium-severity vulnerability (CVSS score of 6.2) affecting Malwarebytes 4.x and 5.x (and Nebula 2020-10-21 and later). The issue occurs when a large number of Firefox preference files cause the parser to ignore other browser configuration files, leading to a denial of service.

Vendor
Malwarebytes
Product
Malwarebytes 4.x and 5.x
CVSS
MEDIUM 6.2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-09
Original CVE updated
2026-06-09
Advisory published
2026-06-09
Advisory updated
2026-06-09

Who should care

Users of Malwarebytes 4.x and 5.x (and Nebula 2020-10-21 and later) should be aware of this vulnerability and take necessary actions to mitigate the risk.

Technical summary

The vulnerability is caused by the parser ignoring other browser configuration files when a large number of Firefox preference files are present. This leads to a denial of service.

Defensive priority

MEDIUM

Recommended defensive actions

  • Users should update Malwarebytes to the latest version to ensure they have the necessary patches.
  • Administrators should review their Malwarebytes configurations to ensure they are not vulnerable to this issue.

Evidence notes

The CVE record [resourceLinkAnnotations:cve-org] and NVD detail [resourceLinkAnnotations:nvd] provide additional information about this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2023-43686 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2023-43686

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2023-43686 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2023-43686

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.