Windows Defender ShieldCrash 0-Day Lets Attackers Read Arbitrary Files as SYSTEM
Unpatched Windows Defender zero-day 'ShieldCrash' PoC lets local attackers read arbitrary files as SYSTEM, apparently bypassing the CVE-2026-69414 patch.
Researcher MSNightmare published a skeleton proof-of-concept for 'ShieldCrash', an unpatched Microsoft Defender flaw enabling arbitrary file reads with SYSTEM privileges that reportedly persists on supported Windows versions after September 2026 updates. It appears to bypass the recent fix for the Malware Protection Engine elevation-of-privilege flaw CVE-2026-69414 (ShieldBreak), patched in engine version 1.1.26080.3. SYSTEM-level file disclosure could expose credentials, application secrets and registry hives and support post-compromise reconnaissance. No active exploitation is confirmed and Microsoft had issued no specific patch or mitigation at disclosure time.
Nearly 22,000 Microsoft Exchange servers remain exposed to critical security flaw (CVE-2026-62911)
About 22,000 Microsoft Exchange servers remain unpatched against critical auth bypass CVE-2026-62911 as a working exploit circulates online.
CVE-2026-62911 is a critical authentication bypass by capture-replay in Microsoft Exchange Server that allows an authorized attacker to elevate privileges over the network, with a CVSS score of 8.0. Microsoft patched the flaw on August 11, 2026, but Shadowserver Foundation scans show roughly 22,000 servers unpatched, with the US (6,200) and Germany (5,100) leading; BSI reports 85% of on-premises Exchange servers in Germany are still vulnerable. The Netherlands' NCSC-NL flagged that a working exploit is circulating, and Exchange 2016/2019 require the Extended Security Updates program for fixes.
Microsoft Patches 398 Flaws Including a Windows Driver Zero
Microsoft's August Patch Tuesday fixes 398 CVEs, including actively exploited Windows zero-day CVE-2026-68820 used by Lazarus for SYSTEM privilege escalation.
Microsoft's August 2026 Patch Tuesday release addresses 398 new vulnerabilities, 62 rated Critical by the Zero Day Initiative, with CVE-2026-68820 (CVSS 7.0), a use-after-free in the afd.sys Windows kernel driver, the only flaw flagged as actively exploited. Check Point Research attributed exploitation of the privilege escalation bug to Lazarus' Operation Dream Job campaign. Four unauthenticated remote code execution flaws rated 9.8 affect Windows DNS Server (CVE-2026-62878, called wormable by ZDI), Windows Deployment Services (CVE-2026-62893), Microsoft QUIC (CVE-2026-62815) and HPC Pack (CVE-2026-59124). The release also completes a two-part SharePoint fix with RCE component CVE-2026-63520, following July's authentication bypass fix CVE-2026-55040.
Microsoft discloses two actively exploited zero-days among 974 vulnerabilities
Microsoft patches 974 flaws in record Patch Tuesday, including two actively exploited Windows zero-days enabling privilege escalation.
Microsoft's largest-ever Patch Tuesday addresses 974 vulnerabilities, with CVE-2026-81963 (Windows Update Stack) and CVE-2026-85880 (Windows Advanced Local Procedure Call) exploited before disclosure. Both zero-days carry CVSS 7.8 ratings and allow privilege escalation. More than 10% of the defects are rated critical, and researchers attribute the record volume to AI-assisted vulnerability discovery without a matching rise in active exploitation.
Microsoft Patches Record 974 Flaws, Including Two Exploited Windows Zero-Days
Microsoft's September Patch Tuesday fixed a record 974 flaws, including two Windows privilege-escalation zero-days actively exploited and added to CISA's KEV catalog.
Microsoft's September 2026 Patch Tuesday addressed a record 974 vulnerabilities (999 including 25 non-Microsoft CVEs), with over 110 rated critical; 723 affect Windows and 111 affect Office. Two Windows privilege-escalation zero-days are actively exploited: CVE-2026-85880, an ALPC heap-based buffer overflow, and CVE-2026-81963, an improper link resolution flaw in the Windows Update Stack, both allowing attackers to gain SYSTEM privileges. CISA added both flaws to its KEV catalog, giving federal civilian agencies until September 22, 2026 to apply fixes. Volexity, Proofpoint, MSTIC, and independent researchers were credited with the reports; notable additional fixes include network-reachable RCEs in Exchange, SharePoint, SQL Server, Remote Desktop Services, DNS, and DHCP.
Chaotic Eclipse Released ShieldCrash, A PoC For Microsoft Defender Zero-Day
Researcher Chaotic Eclipse released ShieldCrash, a PoC showing Microsoft Defender's CVE-2026-69414 patch is incomplete, enabling arbitrary file reads as SYSTEM.
Security researcher Chaotic Eclipse published ShieldCrash, a proof-of-concept exploit for the Microsoft Malware Protection Engine privilege escalation vulnerability CVE-2026-69414 (ShieldBreak). The PoC performs arbitrary file reads with SYSTEM privileges on all supported Windows versions, including systems running the September 2026 security updates and Malware Protection Engine version 1.1.26080.3. The researcher claims Microsoft's patch fixed several exploit paths but missed a specific condition that still enables the attack. His recent releases also include zero-day PoCs targeting Nvidia, Kaspersky, Avast, and CrowdStrike Falcon.
New ‘ShieldCrash’ Zero-Day Exploit Targets Microsoft Defender
Researcher Nightmare Eclipse released ShieldCrash, a Microsoft Defender zero-day PoC bypassing ShieldBreak patches to gain System privileges on Windows.
The researcher known as Nightmare Eclipse released a PoC zero-day exploit dubbed ShieldCrash against Microsoft Defender on fully patched Windows systems. The exploit grants arbitrary file read with System privileges and can be used to drop the SAM database. It bypasses Microsoft's September 3 fixes for ShieldBreak (CVE-2026-69414), which itself bypassed patches for the RoguePlanet race condition (CVE-2026-50656). Microsoft has been contacted for comment and has not yet responded.
Microsoft patches 400+ vulnerabilities, one zero-day under attack (CVE-2026-68820)
Microsoft's August 2026 Patch Tuesday fixes 400+ vulnerabilities, including an actively exploited Windows zero-day (CVE-2026-68820) used by North Korean attackers.
Microsoft's August 2026 Patch Tuesday fixes over 400 vulnerabilities, including CVE-2026-68820, a use-after-free in the Windows Ancillary Function Driver exploited in the wild by North Korean actors deploying a kernel-mode rootkit in Operation Dream Job. Critical unauthenticated remote code execution flaws in Microsoft QUIC (CVE-2026-62815) and Windows DNS (CVE-2026-62878) were also patched, alongside a SharePoint RCE chain combining CVE-2026-63520 with CVE-2026-55040. Researcher Nightmare-Eclipse released ShieldBreak, a PoC bypassing the July RoguePlanet Microsoft Defender patch (CVE-2026-50656), confirmed working by Will Dormann on Windows 11.
Microsoft fixes record 964 flaws, including 2 exploited zero-days
Microsoft's September Patch Tuesday fixes a record 964 CVEs, including two actively exploited Windows privilege-escalation zero-days, CVE-2026-81963 and CVE-2026-85880.
Microsoft's September 2026 Patch Tuesday addresses 964 customer-patchable CVEs (104 Critical, 860 Important), the largest release on record, out of 974 total listed. Two actively exploited zero-days are fixed: CVE-2026-81963, a link-following elevation-of-privilege flaw in the Windows Update Stack, and CVE-2026-85880, a Windows ALPC heap overflow enabling AppContainer sandbox escape, both with CVSS 7.8. Both zero-days were exploited before a patch was available and grant SYSTEM-level access after an initial foothold. The release also includes high-severity RCE fixes for Windows DNS Server, Remote Desktop Services, Exchange Server, SharePoint, and SQL Server.
⚡ Weekly Recap: VMware Exploits, Windows 0-Day, MCP Attacks, Browser Hijacks and More
Weekly recap: suspected China-nexus APT exploited VMware vCenter CVE-2026-59310, Lazarus used Windows zero-day CVE-2026-68820, and macOS flaw dropped Monero miners.
The week's top stories included a suspected China-nexus APT exploiting VMware vCenter CVE-2026-59310 (CVSS 9.8), a directory-traversal flaw enabling arbitrary code execution, with backdoors, reverse SSH and Babuk-derived ransomware deployed, per QUIRSO. NCSC-NL reported active exploitation of macOS Screen Sharing flaw CVE-2026-65400 (CVSS 9.8) to install Monero miners on systems with port 5900 exposed. Lazarus Group exploited Windows zero-day CVE-2026-68820 (CVSS 7.0) in Operation Dream Job, delivering ForestTiger and Troy backdoors to defense and aerospace targets. GeoServer patched a critical SQL injection flaw exploited within hours of disclosure, and Jamf analyzed the new Amnesia Stealer for macOS with live browser control.
U.S. CISA adds Apple macOS, Microsoft SharePoint, Broadcom VMware vCenter, and Microsoft IKE flaws to its Known Exploited Vulnerabilities catalog
CISA adds actively exploited flaws in Microsoft IKE, SharePoint, VMware vCenter, and macOS Screen Sharing to KEV catalog, due August 21.
CISA added four vulnerabilities to its Known Exploited Vulnerabilities catalog: CVE-2026-33824 (Windows IKE remote code execution, CVSS 9.8), CVE-2026-55040 (SharePoint JWT authentication bypass, CVSS 9.1), CVE-2026-59310 (VMware vCenter Syslog path traversal, CVSS 9.8), and CVE-2026-65400 (macOS Screen Sharing improper authentication). The SharePoint flaw combines four weaknesses including alg:none JWT forging to impersonate any user, with Defused researchers observing attackers using Rapid7's PoC against honeypots. The Dutch NCSC confirmed active exploitation of the macOS Screen Sharing flaw on August 15, 2026. Federal agencies must patch by August 21, 2026.
New Microsoft Defender 'ShieldCrash' zero-day grants SYSTEM access
Researcher Nightmare Eclipse released 'ShieldCrash', a zero-day exploit for Microsoft Defender that grants attackers SYSTEM-level access.
An anonymous researcher known as Nightmare Eclipse published a zero-day exploit for Microsoft Defender, dubbed 'ShieldCrash', that yields SYSTEM-level access. The release came immediately after Microsoft rolled out its September 2026 Patch Tuesday security updates. No CVE identifier has been assigned publicly and no in-the-wild exploitation has been reported yet. Microsoft Defender ships by default on Windows, so potential exposure is broad until Microsoft patches the flaw.