Researcher Chaotic Eclipse Unleashes Zero-Day PoC Wave: ShieldCrash Defender Patch Bypass, NVIDIA GreenSection, CrowdStrike FalconFlank
Zero-day researcher Chaotic Eclipse (aka Nightmare Eclipse/MSNightmare) released a week-long run of PoCs: ShieldCrash bypasses the Microsoft Defender ShieldBreak patch (CVE-2026-69414) to read files as SYSTEM, GreenSection hits an unpatched NVIDIA…
Between September 7 and 10, 2026, researcher Chaotic Eclipse — also known as Nightmare Eclipse and MSNightmare — published a series of zero-day proof-of-concept exploits against major security products. The dominant story is ShieldCrash, released September 9: a PoC showing Microsoft's patch for the ShieldBreak elevation-of-privilege flaw in the Microsoft Malware Protection Engine (CVE-2026-69414, CVSS 7.8, fixed September 3, 2026 in engine version 1.1.26080.3, which updates automatically) can be bypassed. The PoC demonstrates arbitrary file reads with SYSTEM privileges on fully patched Windows 10, Windows 11, and Windows Server — enough to dump the SAM database — but does not enable arbitrary writes, code execution, or a full SYSTEM shell. It is the third bypass in a chain: ShieldBreak itself bypassed the fix for RoguePlanet (CVE-2026-50656), and The Register counts ShieldCrash as the researcher's 11th Microsoft zero-day. No new CVE is assigned; Microsoft has not confirmed the bypass, awaits independent reproduction (per Cyber Security News), and has given no patch timeline, though Kevin Beaumont confirmed several of the researcher's other recent exploits work as described. The PoC repository reportedly contains C++ project files, a Warden.dll library, and an EICAR test archive, suggesting interaction with Defender's malware-detection workflow. Earlier, on September 7, the researcher released GreenSection, a PoC for an unpatched out-of-bounds write in NVIDIA's Windows user-mode components, which share a global memory section (\BaseNamedObjects\{52813408-3561-4705-820a-2b3b78be92ba}) with full read/write access for all users; the unstable PoC crashes Vulkan/OpenGL applications and may cross user boundaries or compromise dwm.exe, though impact was not fully investigated, and no CVE or patch exists. On September 9 the researcher also published FalconFlank, a CrowdStrike Falcon Sensor privilege-escalation zero-day abusing the high-privilege Microsoft Office suspicious-macro removal feature on fully updated Windows 11 25H2 and Windows Server 2025 with Falcon Phase 3 Optimal Protection; CrowdStrike is investigating and advises disabling that policy (customers remain covered by Cloud Anti-malware for Microsoft Office Files). Prior releases include HardBreacher (Kaspersky Endpoint Security, since patched) and PrettyPrague (Avast, which dumps the SAM database for a SYSTEM shell and may also affect AVG and Norton). No active exploitation of any flaw has been…
- Researcher identity is reported under multiple aliases: Security Affairs and The Hacker News use 'Chaotic Eclipse' (aka 'Nightmare Eclipse'), while GBHackers and Cyber Security News use 'MSNightmare'; The Register identifies Nightmare…
- ShieldCrash is a PoC bypass of the ShieldBreak patch for CVE-2026-69414 (CVSS 7.8), a high-severity elevation-of-privilege flaw in the Microsoft Malware Protection Engine, originally fixed in engine version 1.1.26080.3 via September 3,…
- The PoC demonstrates arbitrary file reads with SYSTEM privileges on fully patched Windows 10, Windows 11, and Windows Server systems — including those running the September 2026 updates — but not arbitrary writes or a full SYSTEM shell; it…
- ShieldCrash is the third bypass in a series: ShieldBreak (CVE-2026-69414) itself bypassed the fix for RoguePlanet (CVE-2026-50656); SecurityWeek says this suggests Microsoft's patching of the underlying attack path is incomplete.
- It is the researcher's 11th Microsoft zero-day, per The Register; no new CVE has been assigned and Microsoft has neither confirmed the bypass nor committed to a patch timeline.
- The PoC repository reportedly contains C++ project files, a Warden.dll library, and an EICAR test archive, indicating interaction with Defender's malware-detection and file-handling workflow.
- Kevin Beaumont confirmed several of the researcher's recent exploits, including FalconFlank and HardBreacher, work as described; Cyber Security News notes the ShieldCrash claim awaits independent reproduction.
- GreenSection (September 7) is a PoC for an unpatched out-of-bounds write in NVIDIA Windows user-mode components that share a global memory section (\BaseNamedObjects\{52813408-3561-4705-820a-2b3b78be92ba}) with full read/write access for…
Coverage timelineoldest first · each row is one article
- · 9d agoChaotic Eclipse Released GreenSection, A PoC For NVIDIA Memory Corruption Zero-Day
Security Affairs· 52
Researcher Chaotic Eclipse released GreenSection, a PoC exploiting an unpatched out-of-bounds write in NVIDIA Windows user-mode shared memory.
- · 9d agoChaotic Eclipse Released A PoC For NVIDIA GreenSection Memory Corruption Zero-Day
Researcher Chaotic Eclipse released GreenSection, a PoC exploit for an NVIDIA Windows user-mode shared-memory flaw enabling out-of-bounds writes and potential dwm.exe compromise.
Vulnerabilities in this storyAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| 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 ". Microsoft is aware of an elevation of privilege in the Microsoft Malware Protection Engine in Microsoft Defender publicly referred to as "RoguePlanet ". NVD description · AI analysis pending | 7.0 | 11% | PoC |
| — | |
| CVE-2026-69414 | Local Elevation of Privilege in Microsoft Defender Malware Protection Engine CVE-2026-69414, publicly dubbed 'ShieldBreak', is a high-severity (CVSS 3.1: 7.8) elevation-of-privilege flaw in the Microsoft Malware Protection Engine (MMPE) that powers Microsoft Defender, rooted in improper access control and improper privilege management (CWE-284/CWE-269). It is triggered locally: an attacker who already holds low privileges on the machine needs no user interaction (AV:L/AC:L/PR:L/UI:N) to trip the engine's flawed access checks, and successful exploitation yields high impact to confidentiality, integrity, and availability. News coverage reports public PoCs released under the 'ShieldBreak'/'ShieldCrash' names demonstrating SYSTEM-level access on Defender-protected Windows systems, including claims that the shipped patch can be bypassed and arbitrary files read as SYSTEM. Because MMPE ships as the scan engine inside Microsoft Defender, effectively every Defender-protected Windows 10/11 endpoint and server is potentially affected, though the source data specifies no affected engine version ranges. There is no confirmed in-the-wild exploitation (EPSS 0.6%, absent from CISA KEV), but given the public PoC claims, defenders should assume working exploit code exists. Do: Ensure Microsoft Defender and its Malware Protection Engine are fully up to date by installing the latest antimalware platform and security intelligence (definition) updates via Windows Update, WSUS/SCCM/Intune, or Defender for Endpoint, and verify the installed engine version against Microsoft's advisory since PoC reports claim the initial patch can be bypassed. Given the local, low-privilege attack path, prioritize hosts where untrusted users or code run locally, such as shared servers, RDS/terminal hosts, and developer workstations. Monitor Microsoft and researcher channels for follow-up engine updates or revised guidance addressing the reported patch bypass. | 7.8 | <1% |
| masshundreds of millions of Windows endpoints (MMPE is bundled with Microsoft Defender, the default antimalware on modern Windows) |