CVE-2026-105726: Microsoft Defender out-of-bounds read information disclosure

CVE-2026-105726 · Severity: medium · CVSS 5.5 · Published 2026-10-13

Microsoft Defender, which protects Windows systems from malware and threats, contains an out-of-bounds read vulnerability that allows an authenticated attacker to read sensitive information on a local machine. An attacker with local access could exploit this flaw to extract confidential data that would normally be protected, such as system credentials or private files.

Technologies: Microsoft Defender. Vendors: Microsoft.

Quick answers

Is CVE-2026-105726 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-105726 being exploited in the wild.
How severe is CVE-2026-105726?
Medium severity, with a CVSS score of 5.5, published 13 October 2026.
Which products and versions are affected?
Microsoft Defender.
Is there a fix for CVE-2026-105726?
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-2026-105726 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-105726?
Check whether you run Microsoft Defender. 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

An out-of-bounds read in Microsoft Defender permits authenticated local attackers to disclose sensitive information. The vulnerability requires local access and attacker authentication, and results in information disclosure without code execution. A patch is available from Microsoft.

Affected products

  • Microsoft Defender

Timeline

  • 2026-10-13: disclosed

References

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