SharePoint

Top Cybersecurity Stories: SharePoint Exploits Warned by US Authorities, Citrix and WordPress Flaws Lead Weekly Rankings

Security NEXT has published its weekly ranking of the most viewed articles from September 27 to October 3, 2026, highlighting critical vulnerability disclosures and confirmed exploitation cases. US authorities issued warnings about active exploitation of five vulnerabilities affecting SharePoint and WordPress. Citrix NetScaler received multiple vulnerability advisories with two flaws already confirmed as exploited in the wild. Apple released iOS 26.7.1 to address vulnerabilities potentially used in targeted attacks against specific individuals. Other notable incidents include a personal data breach at Times Car car-sharing service and a ransomware attack impacting Keio Electric Railway operations.

Microsoft Copilot Can Surface Overshared Data Despite Permission Boundaries

Microsoft documentation states that Copilot only accesses data authorized for the signed-in user, yet default SharePoint and OneDrive sharing settings often grant broad access that the AI then respects literally. This creates accidental oversharing risks where Copilot retrieves documents shared too widely years earlier. Administrators can use Content Management Assessment and Data access governance reports, including the EEEU report covering the top 100 sites shared in the past 28 days, to identify problematic content. Two distinct controls exist: Restricted Access Control removes access entirely while Restricted Content Discovery hides items from Copilot and search without altering permissions. Sensitivity labels combined with encryption can exclude programmatic access for agents, though Microsoft does not guarantee outright blocking. Interaction logs stored in Microsoft Purview retain user prompts, Copilot responses, and citations to accessed documents, providing an audit trail for oversharing incidents.

Building a Cybersecurity News Aggregator: Story Clustering, Seven Importance Signals and Strict Filtering Thresholds

The idea for an information security news aggregator emerged years ago with the goal of delivering only the most relevant stories while eliminating noise. Early versions relied on the rut5_base_sum_gazeta summarization model and TextRank for importance scoring, but performance remained unsatisfactory. The current system processes roughly one thousand items daily from more than 200 sources and publishes only about 0.5 percent of them. A hybrid approach now combines a transparent seven-feature formula that scores story importance with an LLM that removes irrelevant content and generates concise summaries. The formula incorporates signals such as confirmation count, CVSS severity, exploitation status from KEV, source tier, proximity to Russian readers, depth of analysis, and publication speed. Penalties are applied for vendor self-promotion, webinars, and job postings. Stories are clustered using CVE identifiers, shared trigrams, and named entities to avoid duplicate posts while preserving original reporting.

SOC Incident Analysis Exposes Active Exploitation of CVE-2025-53770 SharePoint ToolShell Auth Bypass and RCE

A detailed walkthrough of Letsdefend SOC342 demonstrates how analysts detected and confirmed exploitation of CVE-2025-53770 targeting SharePoint servers. The alert was triggered by a suspicious unauthenticated POST request to ToolPane.aspx carrying an unusually large payload and a spoofed referer. Investigation revealed that the vulnerable server accepted the request, after which PowerShell commands extracted ASP.NET cryptographic keys, enabling ViewState forgery and remote code execution. Attackers then compiled and dropped additional payloads using csc.exe and created a malicious spinstall0.aspx page that leveraged WScript.Shell to download further malware. Network indicators included the malicious IP 107.191.58.76 flagged by CISA and multiple VirusTotal detections. The server was isolated, files removed, and cryptographic keys rotated to contain the breach.

CISA Adds Three Exploited Vulnerabilities in FortiSandbox and SharePoint to KEV Catalog

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added three actively exploited vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog on July 16, 2026. Two of the flaws affect Fortinet’s FortiSandbox malware analysis product and involve OS command injection issues that can be triggered via specially crafted HTTP requests without requiring authentication. The third vulnerability impacts Microsoft SharePoint and stems from unsafe deserialization of untrusted data, potentially allowing remote code execution over the network. CISA’s action follows public advisories released by the vendors in April and June 2026. The agency is urging organizations to apply available patches and mitigations immediately to reduce the risk of compromise.

CISA Urges Immediate Patching as Multiple SharePoint Server Vulnerabilities Confirmed Exploited

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued an urgent advisory after confirming active exploitation of multiple vulnerabilities in Microsoft SharePoint Server. Four specific CVEs have been added to the Known Exploited Vulnerabilities (KEV) catalog, with one additional flaw flagged by Microsoft as high-risk even without confirmed exploitation. Successful attacks can lead to remote code execution, theft of Internet Information Services (IIS) machine keys, establishment of persistent access, and deployment of malware. CISA recommends applying the latest Microsoft patches immediately, verifying successful installation, enabling the Antimalware Scan Interface (AMSI), and strengthening monitoring through Microsoft Defender Antivirus. Organizations are also advised to avoid direct internet exposure of SharePoint servers and to implement Layer 7 reverse proxies with enhanced logging to reduce the attack surface.