CVE-2026-50656 — Microsoft Malware Protection Engine

As of 2026-06-23, CVE-2026-50656 is a HIGH-severity vulnerability in Microsoft Malware Protection Engine, CVSS v3.1 7.8, EPSS 3.3% (87.2th percentile). Threadlinqs Intelligence links 3 tracked threat campaigns to CVE-2026-50656, most recently “ShieldBreak: Windows Defender Cloud-Hydration Zero-Day Bypasses RoguePlanet Patch (CVE-2026-50656) for SYSTEM-Level Privilege Escalation”.

Last updated: 2026-06-23

What is CVE-2026-50656?

Microsoft is aware of an elevation of privilege in the Microsoft Malware Protection Engine in Microsoft Defender publicly referred to as "RoguePlanet ". We are working to provide a high quality security update that addresses this vulnerability. We will provide information in this CVE when the update is available.

The record classifies CVE-2026-50656 under weakness class CWE-59. Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 88 days ago.

Severity and exploitation probability

CVSS v3.1 base score

7.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:U/RC:C

EPSS (FIRST)

3.3% probability of exploitation in the next 30 days, higher than 87.2% of all scored CVEs

CISA KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog

Threadlinqs priority

9.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability

Published

2026-06-16, last modified 2026-06-23

Is CVE-2026-50656 being exploited?

Weaponised exploit code for CVE-2026-50656 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier.

• 0xBlackash/CVE-2026-50656 (github)
• trickest/cve (trickest)

Affected products and versions

• Microsoft: Malware Protection Engine

How to fix CVE-2026-50656

Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50656. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-50656

3 tracked threats in the Threadlinqs corpus reference CVE-2026-50656, either in the campaign’s CVE list or as an indicator on the campaign record.

• ShieldBreak: Windows Defender Cloud-Hydration Zero-Day Bypasses RoguePlanet Patch (CVE-2026-50656) for SYSTEM-Level Privilege Escalation — CRITICAL · 2026-08-14
• RoguePlanet: Microsoft Defender Elevation of Privilege Vulnerability (CVE-2026-50656) Patched — HIGH · 2026-07-10
• CVE-2026-50656: RoguePlanet Microsoft Defender Zero-Day Local Privilege Escalation (Malware Protection Engine TOCTOU) — HIGH · 2026-06-17

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-06-25. This product uses the NVD API but is not endorsed or certified by the NVD.

Vendor advisory and patch

• msrc.microsoft.com — vendor advisory

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