Threat Intelligence Brief
Curated summary with source attribution
Source: thehackernews.com
Threat Risk: High
Victim: Organizations using Microsoft SharePoint Server
Incident: A critical RCE vulnerability in SharePoint Server was discovered to be significantly more severe than the vendor’s initial classification.
Impact: Authenticated attackers can execute arbitrary code and deploy in-memory webshells to gain persistent server access.
Attacker: Unidentified threat actors
Analysis: CVE-2026-65660 was initially downplayed as a moderate spoofing issue but actually enables authenticated Remote Code Execution (RCE). The flaw exists in the SafeControls list check, where unescaped quotes allow attackers to inject arbitrary .NET classes and trigger code execution via deserialization. Because the vulnerability was initially mislabeled, many organizations may have deprioritized the necessary patches.
Recommendations: Apply the August 11 security updates immediately across all SharePoint environments; Audit legacy SharePoint 2013 installations which remain unsupported and vulnerable; Monitor for unusual web-part modifications and unauthorized .NET class loading
Source: The Hacker News
Editorial note: this post summarizes third-party reporting and links to the original source.
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