Microsoft SharePoint

Critical Microsoft SharePoint Vulnerability Allows Remote Code Execution via SafeControls Bypass

A vulnerability tracked as CVE-2026-65660 with a CVSS score of 8.8 affects Microsoft SharePoint Server 2016, SharePoint Server 2019, and Subscription Edition. The flaw permits an authenticated low-privileged attacker to achieve arbitrary code execution on on-premises servers. It stems from improper handling of quotes in attacker-controlled Register directives within the ToolPane component, bypassing the SafeControls mechanism. This allows registration of dangerous .NET classes followed by deserialization-based remote code execution. Microsoft released patches on August 11, 2026, and initially reported no public disclosure or exploitation. Publication of a detailed technical analysis has now increased the risk for unpatched installations.

CISA Adds Four Exploited Vulnerabilities to KEV Catalog Including Critical macOS Authentication Bypass

The US Cybersecurity and Infrastructure Security Agency has added four newly exploited vulnerabilities to its Known Exploited Vulnerabilities catalog. The flaws affect Apple macOS, Microsoft SharePoint, and VMware vCenter among other products. One of the vulnerabilities, tracked as CVE-2026-65400, allows network-based authentication bypass in macOS Screen Sharing without valid credentials. The issue received a CVSS v3.1 base score of 9.8 and is rated Critical. Apple addressed the flaw in macOS Tahoe 26.6.1, macOS Sequoia 15.7.9, and macOS Sonoma 14.8.9 released on August 6. Federal agencies have been instructed to apply mitigations within three days.

CISA Adds SharePoint and Check Point SmartConsole Flaws to Known Exploited Vulnerabilities Catalog

The US Cybersecurity and Infrastructure Security Agency has added two vulnerabilities to its Known Exploited Vulnerabilities catalog after confirming active exploitation. CVE-2026-50522 affects Microsoft SharePoint and allows remote code execution through untrusted data deserialization, carrying a CVSS v3.1 base score of 9.8. A patch was released on July 14, 2026, though exploitation was not observed at the time of disclosure. CVE-2026-16232 impacts Check Point Software Technologies SmartConsole and stems from an authentication bypass that could let attackers obtain administrative privileges and alter security policies. CISA has directed federal agencies to remediate both issues by July 25, 2026, and Check Point has published associated malicious IP addresses. The agency warns that the flaws pose a broad exploitation risk beyond government systems.

Cybercriminals Exploit Critical SharePoint Vulnerability CVE-2025-53770 for Remote Code Execution

A critical unauthenticated remote code execution flaw in Microsoft SharePoint Server, tracked as CVE-2025-53770 with a CVSS score of 9.8, is being actively exploited in the wild. The vulnerability stems from unsafe deserialization of data sent to on-premises servers and forms part of the ToolShell attack chain alongside CVE-2025-49704 and CVE-2025-49706. Attackers can execute arbitrary commands, install web shells, and steal ASP.NET cryptographic keys to forge authentication tokens and maintain persistence even after patching. The flaw affects SharePoint Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition, while SharePoint Online in Microsoft 365 remains unaffected. Two related variants, CVE-2025-53770 and CVE-2025-53771, were developed to bypass earlier mitigations. Administrators are urged to apply all available patches immediately, restrict internet exposure of SharePoint, and hunt for suspicious files, processes, and scheduled tasks.