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CVE-2026-50522: Patch Critical SharePoint RCE Now

Microsoft patched CVE-2026-50522 (CVSS 9.8), an unauthenticated deserialization RCE in on-premises SharePoint servers, in its July 2026 updates; no exploitation confirmed at disclosure.

CVE-2026-50522 is a critical (CVSS 9.8) deserialization of untrusted data flaw (CWE-502) allowing unauthenticated remote code execution on on-premises Microsoft SharePoint servers. It affects SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition, with fixes shipped in Microsoft's July 14, 2026 security updates; SharePoint Online is not listed as affected. No public evidence of active exploitation of this specific CVE existed at disclosure, though CISA's SSVC judged the attack automatable with total technical impact.

VU#687587: AOMEI Backupper amwrtdrv.sys local privilege escalation vulnerability allows arbitrary writes to physical disks

AOMEI Backupper 8.4.0 driver flaw CVE-2026-12780 lets unprivileged users write physical disks and execute UEFI code, bypassing HVCI and EDR.

CERT/CC issued VU#687587 for CVE-2026-12780, an incorrect permission assignment (CWE-732) in the amwrtdrv.sys kernel driver shipped with AOMEI Backupper 8.4.0. The driver exposes a world-accessible device object without a security descriptor, allowing any unprivileged user to write arbitrary physical disk sectors; with Secure Boot disabled, an attacker can modify the GPT and inject a UEFI payload that executes before the OS loads, bypassing HVCI, EDR, Windows Defender and Hyper-V isolation. On TPM-only BitLocker configurations the attack can capture Volume Master Key material during pre-boot. AOMEI has shipped patches; users who cannot update should uninstall the software or disable the amwrtdrv.sys service, and enabling Secure Boot adds defense in depth.

New Windows Defender ShieldCrash 0-Day Bypasses Microsoft Patch to Read Files as SYSTEM

Researcher's ShieldCrash PoC claims Microsoft Defender still allows arbitrary file reads as SYSTEM on patched Windows, bypassing the CVE-2026-69414 fix.

Researcher MSNightmare released the ShieldCrash proof of concept showing Microsoft Defender can allegedly be made to read arbitrary files with SYSTEM privileges on fully patched Windows systems, bypassing the September 2026 fix for ShieldBreak (CVE-2026-69414). Microsoft has not confirmed the bypass, and the new flaw has no CVE assignment yet. The PoC repository contains C++ project files, a Warden.dll library, and an EICAR test archive, suggesting interaction with Defender's malware-detection and file-handling workflow. Reading files as SYSTEM could expose configuration files, credentials, private keys, and other users' data, though it does not enable code execution.

Microsoft Patch Tuesday Update September 2026 – 974 Vulnerabilities Fixed, Including 2 Zero-Days

Microsoft's September 2026 Patch Tuesday fixes 974 vulnerabilities across Windows and Office, including two actively exploited Windows privilege-escalation zero-days.

Microsoft's September 2026 Patch Tuesday addresses 974 vulnerabilities spanning Windows, Office, SQL Server, SharePoint, Exchange, Azure, and developer tools. Two Windows zero-days are confirmed exploited in attacks: CVE-2026-85880, a Windows ALPC elevation-of-privilege flaw, and CVE-2026-81963, a Windows Update Stack privilege-escalation flaw involving link following. The release also includes Critical fixes for Windows Secure Kernel Mode, VBS Enclave, Excel, and Word.

U.S. CISA adds PaperCut NG/MF flaws to its Known Exploited Vulnerabilities catalog

CISA added two actively exploited PaperCut NG/MF pre-auth flaws to the KEV catalog; federal agencies must patch by September 14.

CISA added CVE-2026-81578 (CVSS 8.8, missing authentication for critical function) and CVE-2026-82078 (CVSS 9.4, unsafe reflection) in PaperCut NG/MF to its Known Exploited Vulnerabilities catalog. Huntress confirmed active pre-authentication RCE exploitation in two customer environments and reproduced the full chain against a clean PaperCut NG 25.0.11 server, chaining the auth bypass into unsafe Java class loading for SYSTEM-level execution. About 47% of roughly 2,500 tracked PaperCut installs still run version 23 or earlier with no patch available, and observed attacker activity was limited to system discovery commands.

Security Affairs · 15d agoVulnerability in the wildCVE-2026-81578CVE-2026-82078

September 2026 Patch Tuesday roundup: Plugs for two zero day holes among almost 1,000 fixes in Windows

Microsoft's September 2026 Patch Tuesday ships 964 fixes including two exploited Windows zero-days (CVE-2026-85880, CVE-2026-81963) and a wormable DNS RCE.

Microsoft's September 2026 Patch Tuesday includes 964 Microsoft vulnerabilities requiring customer action, a record attributed to AI-assisted bug discovery, plus 174 third-party/open-source and 23 Chromium/Edge CVEs. Two zero-days are exploited in the wild: CVE-2026-85880, a Windows ALPC heap overflow enabling AppContainer sandbox escape and privilege escalation, and CVE-2026-81963, a Windows Update Stack escalation to SYSTEM. CVE-2026-69730, an unauthenticated Windows DNS RCE, is not yet exploited but Microsoft expects exploitation, and roughly 20 bugs could be wormable. Separately, SAP issued a critical CVSS 10.0 fix for the EPP component used in S/4HANA and NetWeaver.

CSO Online · 7d agoVulnerability in the wildCVE-2026-85880CVE-2026-81963CVE-2026-69730+2 CVEs1

CVE-2026-50522: Microsoft SharePoint Server RCE Vulnerability

CVE-2026-50522 is an unauthenticated .NET deserialization RCE in SharePoint Server Subscription, 2019, and 2016; Microsoft patched it July 14, 2026.

CVE-2026-50522 (CWE-502) lets unauthenticated attackers send crafted serialized .NET payloads to network-accessible SharePoint endpoints, triggering gadget-chain deserialization and remote code execution under the privileged SharePoint service account. It affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Server 2016 Enterprise; Microsoft published the advisory on July 14, 2026. The EPSS score is 20.346%, but no public PoC exists and the flaw is not in CISA's KEV catalog at publication. Mitigations include applying Microsoft updates, rotating SharePoint machine keys, enabling AMSI, and restricting internet exposure.