NCSC-2026-0236 [1.00] [M/H] Vulnerabilities fixed in Microsoft Defender

unknownpublic exploitCVE-2026-55011 CVE-2026-55012 CVE-2026-50657 CVE-2026-50658 CVE-2026-56178

Microsoft has fixed vulnerabilities in Defender. An attacker can exploit the vulnerabilities to grant themselves elevated privileges, execute arbitrary code with system rights, and/or gain access to sensitive data. The attacker must deceive the victim into downloading and opening a malicious file.

CSIRTS triage

vendor: Microsoft product: Defender Privilege escalation Remote code execution Information disclosure

What: Vulnerabilities allow an attacker to grant themselves elevated privileges, execute arbitrary code, and access sensitive data.
Who is affected: Users of Microsoft Defender.
Urgency: Remediation is necessary as these vulnerabilities could lead to severe impacts, although no exploitation has been reported.
Action: Update Microsoft Defender to the latest version to address the vulnerabilities.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: NCSC-NL Advisories (NL · national-cert · site)
Severity: unknown
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://advisories.ncsc.nl/advisory?id=NCSC-2026-0236

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-550110.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all scored CVEs.
Low exploitation riskCVE-2026-550120.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all scored CVEs.
Low exploitation riskCVE-2026-506570.44% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 36% of all scored CVEs.
Low exploitation riskCVE-2026-506580.19% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 9% of all scored CVEs.
Low exploitation riskCVE-2026-561780.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-55011	coverage & exploitation status	NVD · CVE.org
CVE-2026-55012	coverage & exploitation status	NVD · CVE.org
CVE-2026-50657	coverage & exploitation status	NVD · CVE.org
CVE-2026-50658	coverage & exploitation status	NVD · CVE.org
CVE-2026-56178	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Microsoft Defender

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[NEW] [medium] Microsoft Malware Protection Engine and Defender: Multiple vulnerabilitiescert-bund · 2026-07-15
mediumCVE-2026-56178: Time-of-check time-of-use (toctou) race condition in Microsoft Defender for Endpoint allows an…nvd · 2026-07-14
highCVE-2026-50658: Time-of-check time-of-use (toctou) race condition in Microsoft Defender allows an authorized a…nvd · 2026-07-14
mediumCVE-2026-50657: Exposure of private personal information to an unauthorized actor in Microsoft Defender allows…nvd · 2026-07-14
highCVE-2026-55012: Integer overflow or wraparound in Microsoft Defender allows an unauthorized attacker to execut…nvd · 2026-07-14
highCVE-2026-55011: Integer underflow (wrap or wraparound) in Microsoft Defender allows an unauthorized attacker t…nvd · 2026-07-14