Is CVE-2023-43686 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2023-43686 being exploited in the wild.

How severe is CVE-2023-43686?

Informational severity, with a CVSS score of 5.5, published 9 June 2026.

Which products and versions are affected?

Malwarebytes < 4.6.14.326; Malwarebytes Nebula Endpoint Agent < 2.0.0.64, Protection Service < 4.6.17.334.

Is there a fix for CVE-2023-43686?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2023-43686 attacked?

It is attacked with local access, in a network appliance.

Am I affected by CVE-2023-43686?

Check whether you run Malwarebytes or Malwarebytes Nebula at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2023-43686: Malwarebytes and Nebula denial of service in configuration parser

Q: Which products and versions are affected?

Malwarebytes < 4.6.14.326; Malwarebytes Nebula Endpoint Agent < 2.0.0.64, Protection Service < 4.6.17.334.

Q: Is there a fix for CVE-2023-43686?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

Q: How is CVE-2023-43686 attacked?

It is attacked with local access, in a network appliance.

Q: Am I affected by CVE-2023-43686?

Check whether you run Malwarebytes or Malwarebytes Nebula at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2023-43686 · Severity: info · CVSS 5.5 · Published 2026-06-09

A vulnerability in Malwarebytes and Nebula security software can allow a local user to cause a denial of service. By creating a large number of Firefox preference files, an attacker can overwhelm the software's parser, causing it to ignore other browser configuration files. This effectively disables certain security monitoring or configuration features, potentially leaving the system unprotected or causing the security application to malfunction.

Technologies: Malwarebytes. Vendors: Malwarebytes.

Quick answers

Is CVE-2023-43686 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2023-43686 being exploited in the wild.
How severe is CVE-2023-43686?: Informational severity, with a CVSS score of 5.5, published 9 June 2026.
Which products and versions are affected?: Malwarebytes < 4.6.14.326; Malwarebytes Nebula Endpoint Agent < 2.0.0.64, Protection Service < 4.6.17.334.
Is there a fix for CVE-2023-43686?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2023-43686 attacked?: It is attacked with local access, in a network appliance.
Am I affected by CVE-2023-43686?: Check whether you run Malwarebytes or Malwarebytes Nebula at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is classified as CWE-755 (Improper Handling of Exceptional Conditions) within the Malwarebytes and Nebula configuration parsing engine. A local attacker can trigger this issue by populating a system with an excessive number of Firefox preference files. This condition causes the parser to fail or skip the processing of other critical browser configuration files. The result is a denial of service (DoS) state for the affected security component, potentially bypassing local policy enforcement or monitoring. Patches have been released for Malwarebytes 4 (v4.6.14.326), Malwarebytes 5 (v5.1.5.116), and Nebula (Endpoint Agent v2.0.0.64).

Affected products

Malwarebytes Malwarebytes 4.x < 4.6.14.326
Malwarebytes Malwarebytes 5.x < 5.1.5.116
Malwarebytes Nebula Endpoint Agent < 2.0.0.64, Protection Service < 4.6.17.334

Timeline

2026-06-09: advisory: NVD and Vendor advisory published

References

https://www.malwarebytes.com/secure/cves/cve-2023-43686

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