VulnerabilitiesNov 10, 2026

Microsoft November 2026 Patch Tuesday fixes 1,235 flaws, Outlook zero-day

Microsoft November 2026 Patch Tuesday fixes 1,235 flaws, including an actively exploited Outlook zero-day.

Microsoft's November 2026 Patch Tuesday addresses a record 1,235 vulnerabilities, including one actively exploited zero-day in Microsoft Outlook. The updates include 66 'Critical' vulnerabilities, with 48 allowing Remote Code Execution. The zero-day, CVE-2026-124194, is a spoofing vulnerability that could disclose NTLM account hashes when a user opens a crafted message file.

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The lesson from this incident

Full lesson

Microsoft's November 2026 Patch Tuesday addressed a record 1,235 vulnerabilities, including an actively exploited zero-day in Outlook (CVE-2026-124194) that leaks NTLM account hashes simply by opening a crafted message file. The sheer volume of critical patches — 66 rated Critical, 48 enabling Remote Code Execution — illustrates how quickly an unpatched estate becomes an attractive target. NTLM hash disclosure is particularly dangerous because hashes can be relayed or cracked offline to gain unauthorized access to systems and networks. Organizations that lack timely patching processes or treat Patch Tuesday as optional maintenance risk giving attackers a wide-open window between disclosure and remediation.

What helps against this

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Microsoft affected

Automated patch management
Known holes get closed in days, not months.
For exampleAction1 Patch Management ManageEngine Patch Manager Plus Ivanti Neurons for Patch Management all options
Endpoint detection and response (EDR and XDR)
Malware and hands-on-keyboard attackers on laptops and servers get spotted and stopped.
For exampleHuntress Managed EDR Bitdefender GravityZone Microsoft Defender for Endpoint all options
Email security
Phishing, malware and invoice fraud are filtered out before they reach inboxes.
For exampleProofpoint Core Email Protection Mimecast Email Security Cloudflare Email Security all options

Indicators of Compromise

Extracted by AI from the linked source. Not reviewed by an editor. How this works

cve — CVE-2026-124194

Entities

Microsoft Outlook (product)Microsoft Edge (product)Microsoft (vendor)Entra Device Registration (product)Connect Secure (product)Cisco (vendor)