Microsoft Patches SharePoint RCE Flaw CVE-2026-45659 Across Server Versions

Summary

Microsoft has released patches for CVE-2026-45659, a remote code execution vulnerability in SharePoint that allows authenticated attackers with Site Member permissions to execute arbitrary code without elevated privileges. The flaw stems from unsafe deserialization of untrusted data and carries a CVSS score of 8.8. Updates are available for SharePoint Server Subscription Edition, 2019, and 2016.

Full text

Microsoft Patches SharePoint RCE Flaw CVE-2026-45659 Across Server Versions Ravie LakshmananMay 26, 2026Vulnerability / Enterprise Security Microsoft has rolled out updates to fix a remote code execution vulnerability impacting SharePoint that could be exploited by bad actors in attacks without requiring any specialized conditions to be met. The vulnerability, tracked as CVE-2026-45659, carries a CVSS score of 8.8. It has been assigned an important severity. "Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network," Microsoft said in an advisory released last week. Microsoft noted that the vulnerability could be triggered by any authenticated attacker, and that it does not require administrator or other elevated privileges. "In a network-based attack, an authenticated attacker, who has a minimum of Site Member permissions (PR:L), could execute code remotely on the SharePoint Server," the Windows maker added. Microsoft credited a researcher named MEOW for discovering and reporting the flaw. Updates have been released for the following versions - SharePoint Server Subscription Edition SharePoint Server 2019 SharePoint Enterprise Server 2016 Last month, Microsoft issued fixes for a spoofing vulnerability impacting Microsoft SharePoint Server (CVE-2026-32201, CVSS score: 6.5) that it said has been exploited in the wild. Although the tech giant notes that CVE-2026-45659 is less likely to be exploited, it's essential that users apply the necessary fixes for optimal protection, particularly when considering the fact that several flaws in the collaborative platform have been repeatedly weaponized by attackers over the years. Found this article interesting? Follow us on Google News, Twitter and LinkedIn to read more exclusive content we post. SHARE     Tweet Share Share Share SHARE  CVE, cybersecurity, Deserialization, enterprise security, Microsoft, network security, Patch Management, remote code execution, SharePoint, Vulnerability ⚡ Top Stories This Week Claude Mythos AI Finds 10,000 High-Severity Flaws in Widely Used Software Megalodon GitHub Attack Targets 5,561 Repos with Malicious CI/CD Workflows ThreatsDay Bulletin: Linux Rootkits, Router 0-Day, AI Intrusions, Scam Kits and 25 New Stories Microsoft Warns of Two Actively Exploited Defender Vulnerabilities 9-Year-Old Linux Kernel Flaw Enables Root Command Execution on Major Distros GitHub Internal Repositories Breached via Malicious Nx Console VS Code Extension GitHub Breached — Employee Device Hack Led to Exfiltration of 3,800+ Internal Repos Microsoft Releases Mitigation for YellowKey BitLocker Bypass CVE-2026-45585 Exploit DirtyDecrypt PoC Released for Linux Kernel CVE-2026-31635 LPE Vulnerability ⚡ Weekly Recap: Exchange 0-Day, npm Worm, Fake AI Repo, Cisco Exploit and More Ivanti, Fortinet, SAP, VMware, n8n Patch RCE, SQL Injection, Privilege Escalation Flaws MiniPlasma Windows 0-Day Enables SYSTEM Privilege Escalation on Fully Patched Systems NGINX CVE-2026-42945 Exploited in the Wild, Causing Worker Crashes and Possible RCE Making Vulnerable Drivers Exploitable Without Hardware - The BYOVD Perspective The New Phishing Click: How OAuth Consent Bypasses MFA Developer Workstations Are Now Part of the Software Supply Chain ⭐ Featured Resources Claim ANY.RUN Anniversary Offer for Faster Malware Analysis [Guide] Learn to Detect AI Typosquatting Risks in Your Domain [Guide] Get Key Identity Security Insights From 2026 Snapshot Discover How to Navigate the Era of Constant Cyber Exposure

Indicators of Compromise

• cve — CVE-2026-45659
• cve — CVE-2026-32201

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