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20 articles
Enterprise Guide: Prioritising the June 2026 Patch Tuesday Across 198 CVEs
Security teams face 198 CVEs from Microsoft's June 2026 Patch Tuesday plus concurrent advisories from SAP, Ivanti, Palo Alto, and CISA. This guide provides a decision framework for prioritising remediation across different infrastructure tiers — from internet-facing servers to workstations — with specific guidance for each of the highest-risk vulnerabilities.
Microsoft June 2026 Patch Tuesday: 198 CVEs and Six Zero-Days Including Wormable CVSS 9.8 HTTP.sys Flaw
Microsoft's June 2026 Patch Tuesday addresses 198 vulnerabilities across Windows, Office, Azure, and server components — including three CVSS 9.8 critical remote code execution flaws and six publicly disclosed zero-days. HTTP.sys CVE-2026-47291 is wormable, requiring no authentication or user interaction against any Windows Server with IIS or HTTP API exposed.
VS Code Adds Two-Hour Extension Auto-Update Delay to Reduce Supply Chain Attack Window
Microsoft has released VS Code 1.101 with a configurable two-hour delay on automatic extension updates. The change is a direct response to supply chain attacks in which malicious updates were pushed to popular extensions, executing on developer machines within minutes of publication. The delay gives security teams a detection window before malicious updates execute across the developer fleet.
Pwn2Own Demonstrates Second Distinct SharePoint RCE Chain — Five Days After Patch Tuesday Fixed CVE-2026-40365
Researchers at Pwn2Own Berlin 2026 demonstrated a multi-bug SharePoint Server remote code execution chain that is entirely distinct from CVE-2026-40365, the SharePoint RCE patched in the 12 May Patch Tuesday. The new chain, targeting SharePoint's server-side processing pipeline, has no patch and will not receive one for up to 90 days.
Microsoft May 2026 Patch Tuesday Fixes 120 Vulnerabilities — No Zero-Days but Wormable RCEs Demand Immediate Action
Microsoft released 120 security fixes in May's Patch Tuesday update, including 17 Critical-rated vulnerabilities and no actively exploited zero-days. Among the most significant are a network-based Windows DNS Client RCE and an authenticated SharePoint Server RCE. Security teams should prioritise network-facing systems within 48 hours.
Microsoft Issues Emergency Patch KB5091157 After April Updates Crash Domain Controllers
Microsoft's April 2026 Patch Tuesday updates triggered LSASS crash-reboot loops on non-Global Catalogue domain controllers in PAM-enabled deployments and forced some Windows Server 2025 systems into BitLocker recovery mode. Emergency out-of-band updates were released April 19 for all affected Server versions. Immediate installation is required — affected DCs cause complete authentication outages across their domains.
Microsoft Entra Passkeys Rolling Out to All Windows Devices — Phishing-Resistant MFA Now Generally Available
Microsoft has begun rolling out Entra passkey support to managed, unmanaged, and shared Windows devices, with general availability set for mid-June 2026. Passkeys close the credential-phishing gap that conventional passwords, SMS codes, and TOTP leave open, and enterprise deployment is now achievable at scale through existing Conditional Access policies.
Microsoft Bing Remote Code Execution via Deserialization — CVSS 10.0 Patch Now
A critical CVSS 10.0 unauthenticated RCE vulnerability in Microsoft Bing allows attackers to execute arbitrary code over the network via unsafe deserialization. Patched in April 2026 Patch Tuesday — update immediately.
Microsoft Entra ID Entitlement Management SSRF (CVE-2026-35431, CVSS 10.0) — Cloud IAM Attack Surface Disclosed Before Silent Server-Side Fix
A perfect-score SSRF vulnerability in Microsoft Entra ID Entitlement Management allowed unauthenticated network-accessible exploitation of Microsoft's cloud identity governance platform. Microsoft patched it server-side with no customer action required, but the disclosure surfaces a structural question enterprise security teams need to answer: how do you monitor for exploitation of a vulnerability in infrastructure you don't control?
Microsoft Issues Emergency Patch for ASP.NET Core DataProtection Key Exposure — CVE-2026-40372
A critical security regression in Microsoft.AspNetCore.DataProtection (CVSS 9.1) introduced in .NET 10.0.0 causes encryption keys to leak on Linux deployments. Applications using cookie authentication, anti-forgery tokens, or TempData are at immediate risk. Update to .NET 10.0.7 now.
April Patch Tuesday Bug Crashes LSASS on PAM-Enabled Domain Controllers — No Fix Yet
KB5082063, Microsoft's April 2026 cumulative update, is causing LSASS to crash on non-Global Catalog domain controllers in Privileged Access Management environments, triggering unrecoverable reboot loops that take down Active Directory authentication. Microsoft has confirmed the issue across all Windows Server versions from 2016 to 2025 and is developing a corrected update, but none is available yet.
Microsoft Closes APT29's Favourite Phishing Door With New RDP File Protections
The April 2026 Windows update introduces mandatory security warnings and redirections-blocked-by-default for RDP connection files, directly countering the technique used by APT29 and other threat actors to silently redirect local drives and harvest credentials. Organisations using Windows 10 and 11 should confirm the KB is deployed.
Microsoft April 2026 Patch Tuesday: 167 Flaws Patched Including Two Zero-Days
Microsoft's April 2026 Patch Tuesday addresses 167 vulnerabilities, including an actively exploited SharePoint spoofing zero-day (CVE-2026-32201) and a publicly disclosed Defender elevation-of-privilege flaw. Eight Critical-rated vulnerabilities include a CVSS 9.8 IKE RCE and a Critical Active Directory RCE assessed as exploitation more likely.
CISA Flags SharePoint Zero-Day CVE-2026-32201 as Actively Exploited — Patch Arrives Tomorrow
CISA has added CVE-2026-32201, a Microsoft SharePoint Server spoofing vulnerability under active exploitation, to the KEV catalogue with a 28 April remediation deadline. The timing is unusual: Microsoft has not yet released a patch as of this alert, with the fix expected in tomorrow's Patch Tuesday release. Organisations must decide whether to implement mitigations today or accept overnight exposure until the patch lands.
CISA Adds Seven CVEs to KEV Including Decade-Old Microsoft Bugs Exploited by Storm-1175
CISA has added seven vulnerabilities to the Known Exploited Vulnerabilities catalogue, including four Microsoft flaws spanning from 2012 to 2025 being actively leveraged by the Storm-1175 ransomware group. The additions highlight a persistent patching blind spot: vulnerabilities patched years ago that never made it into legacy system maintenance cycles, now routinely weaponised for initial access and privilege escalation.
BlueHammer Windows LPE Zero-Day Gives Attackers SYSTEM Access — No Patch Available
A publicly disclosed zero-day local privilege escalation vulnerability in Windows Defender's signature-update mechanism allows any authenticated user to escalate to SYSTEM. Named BlueHammer by researchers at Cyderes, the flaw has a working public exploit and no Microsoft patch as of publication. Security teams should implement interim mitigations immediately.
Secure Boot Certificates Expire June 2026 — Enterprise Action Window Is Now
Microsoft's 2011 Secure Boot signing certificates expire on 26 June 2026, with the Windows bootloader certificate following in October. Organisations that fail to apply firmware and OS updates before these deadlines lose the ability to receive boot-level security fixes and risk UEFI bootkit exposure. Microsoft has begun displaying warnings in Windows Security app in April 2026, but the update process requires OEM firmware coordination that takes weeks.
April Windows Update Enforces AES-Only Kerberos — RC4 Fallback Blocked Across Active Directory
Microsoft's April 2026 cumulative update moves Windows domain controllers into AES-only Kerberos enforcement mode, permanently blocking RC4-HMAC as an authentication fallback under CVE-2026-20833. Organisations with legacy service accounts or unmanaged devices that have not set the msDS-SupportedEncryptionTypes attribute will begin seeing Kerberos authentication failures when the update is deployed.
March 2026 Brought 83 Patch Tuesday CVEs and Three CISA KEV Additions — How to Prioritise
March 2026's Patch Tuesday addressed 83 vulnerabilities including three critical Office RCEs, an Active Directory privilege escalation now in CISA's KEV catalogue, and a Kerberos security feature bypass. Add three separate CISA KEV additions throughout the month — F5 BIG-IP, Citrix NetScaler, and Active Directory — and security teams are managing a substantial patching backlog entering April. This analysis cuts through the volume to identify where to focus.
Active Directory Privilege Escalation CVE-2026-25177 Added to CISA KEV — Domain Admin Risk via SPN Abuse
CVE-2026-25177, a privilege escalation vulnerability in Active Directory Domain Services patched in March's Patch Tuesday, has been added to CISA's Known Exploited Vulnerabilities catalogue. An authenticated attacker with low-privileged domain credentials can exploit improper SPN and UPN name validation to escalate to domain administrator level. The KEV addition confirms in-the-wild exploitation approximately three weeks after patching was available.
Commentary tagged #microsoft
When Microsoft, SAP, Ivanti, and Palo Alto All Patch Critical Flaws on the Same Day, We Have a Coordination Problem
The week of 9 June 2026 delivered critical security patches from at least four major vendors on the same day, plus a Linux kernel PoC, plus a CISA KEV batch. The security community has created a coordination structure — Patch Tuesday — that has the opposite of its intended effect: it concentrates defender workload in a single week every month while giving attackers 30 predictable days to prepare.
CipherWatch Editorial
Security Intelligence Platform
198 CVEs in One Day. Something Has Gone Wrong With How We Do Patch Management.
Microsoft's June 2026 Patch Tuesday drops 198 vulnerabilities in a single Tuesday, including six zero-days and three CVSS 9.8 remote code execution flaws. Meanwhile SAP patches 21 flaws on the same day, Cisco issues a critical advisory, and a Linux kernel PoC goes public. The security community has normalised a monthly event so large that no enterprise team can actually process it — and that normalisation is itself the problem.
CipherWatch Editorial
Security Intelligence Platform
Patch Tuesday Is Not a Patching Programme
Every second Tuesday, the industry runs a collective sprint to triage, test, and deploy hundreds of Microsoft patches before the next cycle begins. We call this a patching programme. It isn't. It's a treadmill — and the real security question is whether we're measuring the right thing.
CipherWatch Editorial
Security Intelligence Platform