Microsoft Shatters Patch Tuesday Record With 974 CVE Fixes in September 2026
Microsoft's September 2026 Patch Tuesday fixes a record 974 CVEs, including two actively exploited Windows zero-days, CVE-2026-85880 and CVE-2026-81963.
Microsoft fixed a record 974 CVEs in its September 2026 Patch Tuesday, surpassing the previous record of 570 in July 2026, with Windows affected by 723 flaws and Office by 111, including 119 critical vulnerabilities. Two zero-days are actively exploited: CVE-2026-85880, a 7.8 heap-based buffer overflow in Windows ALPC allowing AppContainer privilege escalation, and CVE-2026-81963, an improper link resolution flaw in the Windows Update Stack enabling local privilege escalation. Microsoft attributed the update surge partly to agentic AI tools used to discover zero-day vulnerabilities, and researchers highlighted critical RCE flaws in Windows DNS, DHCP and Deployment Services as priorities.
Hackers Exploit Marimo RCE to Steal AWS Credentials and Reach Bastion Host in 8 Seconds
Attackers exploited pre-auth RCE CVE-2026-39987 in Marimo notebooks to steal AWS credentials and SSH into a bastion host in eight seconds.
Sysdig Threat Research Team documented an intrusion abusing CVE-2026-39987, an unauthenticated RCE in Marimo's terminal WebSocket endpoint affecting versions up to 0.20.4 and fixed in 0.23.0. The attacker harvested AWS credentials from the host environment and Redis backend, queried AWS Secrets Manager to retrieve an SSH private key, and authenticated to an internet-facing SSH bastion host just eight seconds after opening the WebSocket session. Human-operated custom tooling, not an AI agent, executed the full exploit-to-lateral-movement chain.
CVE-2022-22965: Spring Core Remote Code Execution Vulnerability Exploited In the Wild (SpringShell) (Updated)
Attackers actively exploit Spring Framework RCE CVE-2022-22965 (SpringShell, CVSS 9.8) to deploy webshells; patches 5.3.18/5.2.20 shipped March 31, 2022.
CVE-2022-22965 enables unauthenticated remote code execution in the widely used Spring Framework (CVSS 9.8), which Unit 42 has observed being exploited in the wild. The flaw stems from getCachedIntrospectionResults exposing the class object during parameter binding, letting attackers manipulate the class loader to modify Tomcat logging and upload a JSP webshell. Public PoCs require JDK 9+, Tomcat, WAR packaging, and spring-webmvc or spring-webflux dependencies on Spring 5.3.0-5.3.17, 5.2.0-5.2.19, or older. Fixes shipped in Spring Framework 5.3.18 and 5.2.20; the related Spring Cloud Function flaw CVE-2022-22963 was patched March 29, 2022.
CISA Adds Seven Exploited Flaws as Attackers Deploy Reverse Shells and Crypto Miners
CISA added seven actively exploited vulnerabilities to its KEV catalog, including SonicWall SMA 1000 SSRF CVE-2026-83548, amid campaigns deploying reverse shells and crypto miners.
CISA's KEV additions cover flaws in SonicWall SMA 1000 (CVE-2026-83548, CVE-2026-83549), Sangoma Switchvox (CVE-2026-9586), JFrog Artifactory (CVE-2026-82329), Kludex Starlette (CVE-2026-48710), Kestra OSS (CVE-2026-49869) and Berri LiteLLM's MCP endpoint (CVE-2026-59822). SonicWall confirmed active exploitation of the SMA 1000 flaws, while Microsoft and Wiz reported attackers chaining LiteLLM flaws CVE-2026-42271 and CVE-2026-48710 to fingerprint hosts, steal provider API keys and deploy XMRig miners on AI infrastructure. Wiz linked exploitation of the LiteLLM chain to the Qilin ransomware group, and Microsoft detailed a Kestra compromise chain ending in cryptocurrency mining and data harvesting via exposed RAGFlow flaws.
Week in review: Linux rootkit deployed on F5 BIG-IP APM devices, Cisco FMC bugs exploited
Weekly roundup: Cisco FMC and N-able N-central zero-days exploited in the wild, MikroTik RouterOS hijacks, Microsoft Patch Tuesday ships two exploited zero-days.
State-sponsored and financially-motivated attackers are actively exploiting CVE-2026-20079, a critical authentication bypass in Cisco Secure Firewall Management Center (FMC), alongside CVE-2026-20316. N-able issued an emergency hotfix for CVE-2026-86218, a critical pre-auth RCE in the N-central RMM platform exploited in the wild. CERT Polska disclosed six RouterOS vulnerabilities being chained to hijack internet-exposed MikroTik devices. Microsoft's September 2026 Patch Tuesday shipped a record patch count including two zero-days, while roughly 67,000 Trezor customers faced phishing after a shipping-partner breach and researchers privately disclosed a zero-click WeChat worm to Tencent.
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.