Microsoft Office zero-day lets malicious documents slip past security checks


Microsoft issued an emergency patch for a high-severity zero-day vulnerability in Office that allows attackers to bypass document security checks and is being exploited in the wild via malicious files.

Microsoft pushed the emergency patch for the zero‑day, tracked as CVE-2026-21509, and classified it as a “Microsoft Office Security Feature Bypass Vulnerability” with a CVSS score of 7.8 out of 10. The flaw allows attackers to bypass Object Linking and Embedding (OLE) mitigations that are designed to block unsafe COM/OLE controls inside Office documents. This means a malicious attachment could infect a PC despite built-in protections.

Read more…
Source: Malwarebytes Labs


Sign up for the Cyber Security Review Newsletter
The latest cyber security news and insights delivered right to your inbox


Related:

  • CVE-2023-5950 Rapid7 Velociraptor Reflected XSS

    November 10, 2023

    This advisory covers a specific issue identified in Velociraptor and disclosed by a security code review. CVSS · HIGH · 8.6/10 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L Scoring scenario: GENERAL AattackVector: NETWORK AttackComplexity: LOW PrivilegesRequired: NONE Read more… Source: Rapid7  

  • CVE-2023-47246: SysAid Zero-Day Vulnerability Exploited By Lace Tempest

    November 9, 2023

    On November 8, 2023, IT service management company SysAid disclosed CVE-2023-47426, a zero-day path traversal vulnerability affecting on-premise SysAid servers. According to Microsoft’s threat intelligence team, it has been exploited in the wild by DEV-0950 (Lace Tempest) in “limited attacks.” In a social media thread published the evening of November 8, Microsoft emphasized that Lace Tempest ...

  • SysAid warns customers to patch after ransomware gang caught exploiting new zero-day flaw

    November 9, 2023

    Software maker SysAid is warning customers that hackers linked to a notorious ransomware gang are exploiting a newly discovered vulnerability in its widely used IT service automation software. SysAid chief technology officer Sasha Shapirov confirmed in a blog post Wednesday that attackers are exploiting a zero-day flaw affecting its on-premises software. A vulnerability is considered a ...

  • FBI: Ransomware Actors Continue to Gain Access through Third Parties and Legitimate System Tools

    November 8, 2023

    The Federal Bureau of Investigation (FBI) is releasing this Private Industry Notification to highlight ransomware initial access trends and encourage organizations to implement the recommendations in the “Mitigations” section to reduce the likelihood and impact of ransomware incidents. Threat As of July 2023, the FBI noted several trends emerging or continuing across the ransomware environment and ...

  • Rapid7 Observed Exploitation of Atlassian Confluence CVE-2023-22518

    November 6, 2023

    As of November 5, 2023, Rapid7 Managed Detection and Response (MDR) is observing exploitation of Atlassian Confluence in multiple customer environments, including for ransomware deployment. We have confirmed that at least some of the exploits are targeting CVE-2023-22518, an improper authorization vulnerability affecting Confluence Data Center and Confluence Server. Atlassian published an advisory for the vulnerability ...

  • New Report On Suffolk County Cyber Attack Raises Questions

    November 6, 2023

    The former IT commissioner for the Suffolk County Clerk’s department did not alert county officials that the computer network in the clerk’s office was responding to a “radical malware attack” until eight hours after he was alerted, the Press has learned. The Center for Internet Security (CIS) sent an email at 3 a.m. on Sept. 8, ...