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Weekly Cybersecurity Newsletter Bulletin – Microsoft 0-day, FortiOS, PAN-OS Flaw, Revolut Data Breach, and 20+ Stories

Weekly roundup: Microsoft patches 973 flaws including two actively exploited zero-days; FortiOS CAPWAP flaw deploys PivotC2 RAT; PAN-OS root RCE disclosed.

Microsoft's September 2026 Patch Tuesday fixed 973 vulnerabilities, including two zero-days under active exploitation: CVE-2026-85880 (Windows ALPC) and CVE-2026-81963 (Windows Update Stack), both elevation-of-privilege bugs. SOCRadar reported active exploitation of CVE-2025-25249 (CVSS 9.8) in FortiOS CAPWAP, deploying a Node.js RAT called PivotC2 that exfiltrates Exchange mailboxes to Wasabi cloud storage; 178 devices were compromised out of 30,000 scanned IPs, attributed to a Russian-speaking financially motivated group. Palo Alto disclosed CVE-2026-0310, a 9.2-rated buffer overflow enabling root code execution on PA-Series firewalls, and Fortinet disclosed CVE-2026-84393, a ZTNA certificate validation MITM flaw. Cyera also revealed CVE-2026-6471 ('PostGREShell'), a 12-year-old PostgreSQL logical-decoding flaw allowing code execution via REPLICATION-privileged accounts.

Chaotic Eclipse Releases Crowdstrike Falcon ZeroDay FalconFlank

Researcher Chaotic Eclipse released FalconFlank, a PoC zero-day privilege escalation exploit against CrowdStrike Falcon's Microsoft Office macro removal feature.

Security researcher Chaotic Eclipse (also known as Nightmare Eclipse) published FalconFlank, a proof-of-concept zero-day exploit for a privilege escalation flaw in CrowdStrike Falcon Sensor. It abuses the Microsoft Office file malicious macro removal remediation feature, which runs with high privileges, and works on fully updated Windows 11 25H2 and Windows Server 2025 with Falcon Phase 3 Optimal Protection. CrowdStrike says it is investigating and advises customers to disable the Microsoft Office File Suspicious Macro Removal Windows policy. The same researcher recently released zero-day PoCs against Kaspersky Endpoint Security (HardBreacher) and Avast Antivirus (PrettyPrague), the latter dumping the SAM database for a SYSTEM shell.

Security Affairsupdated · 5d agofirst · 6d agoExploit / PoC 8 sources1· 1 read

Chaotic Eclipse Released GreenSection, A PoC For NVIDIA Memory Corruption Zero-Day

Researcher Chaotic Eclipse released GreenSection, a PoC exploiting an unpatched out-of-bounds write in NVIDIA Windows user-mode shared memory.

Security researcher Chaotic Eclipse disclosed an 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 to all users. The PoC crashes applications running Vulkan or OpenGL; the researcher says the bug could cross user boundaries or compromise dwm.exe but did not fully assess the impact. No CVE has been assigned and no patch is mentioned. The researcher recently released zero-day PoCs against Kaspersky, Avast, and CrowdStrike Falcon.

Security Affairs · 8d agoExploit / PoC 2 sources

Nightmare Eclipse Drops CrowdStrike, Nvidia, Avast Zero-Day Exploits

Researcher Nightmare Eclipse released working zero-day PoCs for Avast, CrowdStrike Falcon, and Nvidia, prompting a Gen patch, CrowdStrike mitigation, and Nvidia investigation.

Security researcher Nightmare Eclipse released three zero-day exploits within a short window: PrettyPrague targeting the Avast sandbox for full system privileges (possibly affecting other GenDigital products including AVG and Norton), FalconFlank exploiting CrowdStrike Falcon Sensor's Office malicious macros remediation feature for privilege escalation, and GreenSection targeting an out-of-bounds memory write in a shared global memory section used by Nvidia user-mode components. GenDigital said it has fixed the Avast issue; CrowdStrike advised disabling the Microsoft Office File Suspicious Macro Removal policy setting; Nvidia said it is actively investigating the PoC. Kevin Beaumont reported that the Avast, CrowdStrike, and Kaspersky exploits work. The researcher previously released the HardBreacher privilege escalation zero-day in Kaspersky endpoint security, patched August 31.

SecurityWeek · 8d agoExploit / PoC

Researcher Publishes CrowdStrike Privilege Escalation Zero Day

Researcher NightmareEclipse published FalconFlank, a zero-day local privilege escalation in CrowdStrike Falcon Sensor abusing its Office malicious macro remediation feature.

A researcher known as Nightmare Eclipse published details of FalconFlank, a zero-day privilege escalation that abuses the Microsoft Office malicious macro removal feature in CrowdStrike Falcon Sensor, verified working on fully updated Windows 11 25H2 and Windows Server 2025 with Falcon Phase 3 Optimal Protection. CrowdStrike urged customers to disable the Office File Suspicious Macro Removal policy while it investigates, noting customers remain protected via Cloud Anti-malware for Microsoft Office Files; no CVE has been assigned. The same researcher previously released the Exploitarium dump of over 30 PoC exploits, and researcher Kevin Beaumont confirmed FalconFlank works.

Infosecurity Magazine · 8d agoExploit / PoC

Prolific Microsoft 0-day hunter drops CrowdStrike Falcon exploit PoC

Researcher Nightmare Eclipse released a PoC for FalconFlank, a privilege escalation zero-day in CrowdStrike Falcon's Office macro remediation feature.

Researcher Nightmare Eclipse published a zero-day PoC dubbed FalconFlank targeting CrowdStrike Falcon's Microsoft Office malicious macro removal feature, achieving privilege escalation on fully updated Windows 11 25H2 and Windows Server 2025 with Optimal Protection and macro removal enabled. Kevin Beaumont independently confirmed the exploit works. The same researcher also released HardBreacher, an elevation-of-privilege bug in Kaspersky Endpoint (since fixed via update), PrettyPrague, an Avast Sandbox flaw that dumps the SAM database for a SYSTEM shell (Gen Digital is developing a patch), and GreenSection, an Nvidia memory corruption bug that crashes systems. CrowdStrike advises customers to disable the Suspicious Macro Removal Windows policy while it investigates.

The Register · Security · 12d agoExploit / PoC

Researcher Releases FalconFlank PoC Showing Privilege Escalation in CrowdStrike Falcon

Researcher Chaotic Eclipse released FalconFlank, a zero-day privilege escalation PoC abusing CrowdStrike Falcon's Office macro remediation; CrowdStrike is investigating and issued a tech alert.

Researcher Chaotic Eclipse published FalconFlank, a proof-of-concept zero-day local privilege escalation in CrowdStrike Falcon Sensor that abuses the Microsoft Office malicious macros remediation feature, tested on fully updated Windows 11 25H2 and Windows Server 2025. CrowdStrike said it is investigating, advised disabling the Microsoft Office File Suspicious Macro Removal policy, and pointed customers to a FalconFlank tech alert, noting cloud anti-malware protection remains active. The article also covers related PoCs from the same researcher: HardBreacher against Kaspersky (fixed via update), ShieldBreak (CVE-2026-69414) against Microsoft Defender, an unpatched patch bypass of CVE-2026-50656, GreenSection against NVIDIA, and PrettyPrague against Avast, which Gen Digital patched in versions 26.7.11086 and 26.8.11125.

Chaotic Eclipse Releases GenDigital Avast Antivirus ZeroDay PrettyPrague

Researcher Chaotic Eclipse released PrettyPrague, a PoC zero-day privilege escalation exploit against fully patched GenDigital Avast Antivirus.

Security researcher Chaotic Eclipse (also known as INFINITE NIGHTMARE or MSNightmare) published a PoC named PrettyPrague exploiting a zero-day privilege escalation flaw in Avast Antivirus. The PoC abuses a flaw in the Avast Sandbox to dump the Windows SAM database and spawn a SYSTEM-level shell, reportedly working on fully patched Avast and patched Windows 11 25H2. The researcher believes the flaw may also affect other GenDigital products such as AVG and Norton. It follows his recent HardBreacher PoC for a Kaspersky Endpoint Security privilege escalation flaw.

Security Affairs · 14d agoExploit / PoC

Chaotic Eclipse Releases Kaspersky Zero

Researcher Chaotic Eclipse released HardBreacher, a PoC privilege-escalation exploit for Kaspersky Endpoint Security on fully patched Windows 11 25H2.

Security researcher Chaotic Eclipse, also known as INFINITE NIGHTMARE and Nightmare-Eclipse, released a PoC zero-day exploit named HardBreacher targeting Kaspersky Endpoint Security v14.0.0.504. The exploit achieves privilege escalation on fully patched Windows 11 25H2, creating a DLL in System32 with full user permissions and potentially disrupting Kaspersky's UI process and file-access controls. The PoC is unstable and may require repeated attempts; Kaspersky claims it has already addressed the vulnerability.

Security Affairs · 14d agoExploit / PoC1

ShieldBreak Zero-Day PoC Claims Microsoft Defender Patch Bypass With SYSTEM Access

Researcher Chaotic Eclipse released ShieldBreak PoC, a claimed patch bypass for Microsoft Defender flaw CVE-2026-50656, now tracked as CVE-2026-69414.

Researcher Chaotic Eclipse released a PoC for ShieldBreak, a claimed full patch bypass of Microsoft Defender flaw CVE-2026-50656 (RoguePlanet), which can yield SYSTEM privileges. Independent researchers Kevin Beaumont and Will Dormann validated the exploit on Windows 11 25H2 and Windows Server 2025, noting it requires Defender to be enabled. Microsoft assigned CVE-2026-69414 (CVSS 7.8) with an 'Exploitation More Likely' assessment and is investigating, but has not yet released a patch. The article also notes CISA's KEV addition of the actively exploited Windows AFD.sys flaw CVE-2026-68820.

ShieldBreak: New Windows Zero-Day Bypasses Microsoft’s RoguePlanet Patch

Researcher Chaotic Eclipse published a PoC bypassing Microsoft's CVE-2026-50656 Defender patch, enabling SYSTEM-level code execution on fully patched Windows systems.

Security researcher Chaotic Eclipse released a proof-of-concept for ShieldBreak, a Microsoft Defender zero-day that fully bypasses the patch for CVE-2026-50656 (RoguePlanet), a race condition in the Malware Protection Engine (mpengine.dll) allowing SYSTEM-level code execution. The PoC was tested on Windows 11 25H2 and Windows Server 2025 with a 100% success rate, and Windows 10 is also vulnerable though not supported by the PoC; the flaw may also leak 8 bytes of memory. Microsoft's MSRC had criticized the researcher's repeated uncoordinated disclosures, including YellowKey (BitLocker bypass), GreenPlasma, and LegacyHive (User Profile Service LPE).

Security Affairs · Aug 12, 2026Exploit / PoCCVE-2026-50656