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:

  • How fiends abuse an out-of-date Microsoft Windows driver to infect victims

    April 24, 2023

    Ransomware spreaders have built a handy tool that abuses an out-of-date Microsoft Windows driver to disable security defenses before dropping malware into the targeted systems. This detection evasion utility, which Sophos X-Ops researchers are calling AuKill, is the latest example in a growing trend where miscreants either abuse a legitimate driver to disable, silence or otherwise ...

  • Google patches another actively exploited Chrome zero-day

    April 19, 2023

    Google has released a security update for the Chrome web browser to fix the second zero-day vulnerability found to be exploited in attacks this year. “Google is aware that an exploit for CVE-2023-2136 exists in the wild,” reads the security bulletin from the company. Read more… Source: Bleeping Computer  

  • CISA Releases Four Industrial Control Systems Advisories

    April 18, 2023

    CISA released four Industrial Control Systems (ICS) advisories on April 18, 2023. These advisories provide timely information about current security issues, vulnerabilities, and exploits surrounding ICS. CISA encourages users and administrators to review the newly released ICS advisories for technical details and mitigations: ICSA-23-108-01 Omron CSCJ Series ICSA-23-108-02 Schneider Electric Easy UPS Online Monitoring Software Read more… Source: U.S. Cybersecurity ...

  • Update now: Google emits emergency fix for zero-day Chrome vulnerability

    April 17, 2023

    Google on Friday released an emergency update for Chrome to address a zero-day security flaw. The vulnerability, tracked as CVE-2023-2033, can be exploited by a malicious webpage to run arbitrary code in the browser. Thus, surfing to a bad website with a vulnerable browser could lead to your device being hijacked. Exploit code for this hole ...

  • Multiple Internet to Baseband Remote Code Execution Vulnerabilities in Exynos Modems

    April 16, 2023

    In late 2022 and early 2023, Project Zero reported eighteen 0-day vulnerabilities in Exynos Modems produced by Samsung Semiconductor. The four most severe of these eighteen vulnerabilities (CVE-2023-24033, CVE-2023-26496, CVE-2023-26497 and CVE-2023-26498) allowed for Internet-to-baseband remote code execution. Tests conducted by Project Zero confirm that those four vulnerabilities allow an attacker to remotely compromise a phone ...

  • Linux kernel logic allowed Spectre attack on ‘major cloud provider’

    April 13, 2023

    The Spectre vulnerability that has haunted hardware and software makers since 2018 continues to defy efforts to bury it. On Thursday, Eduardo (sirdarckcat) Vela Nava, from Google’s product security response team, disclosed a Spectre-related flaw in version 6.2 of the Linux kernel. Read more… Source: The Register