Vulnerability in Windows allows Windows Defender antivirus updates to be disabled
Quick Look
- Security researcher Abdelhamid Naseri discovered the BigDiskBuster vulnerability in Windows, which allows attackers to disable Windows Defender antivirus database updates, leaving systems vulnerable to new threats.
- The vulnerability affects all current versions of Microsoft's OS and is reminiscent of the old UnDefend vulnerability from April 2026.
AI-generated summary
Why It Matters
The BigDiskBuster vulnerability allows you to disable Windows Defender antivirus database updates, which makes systems vulnerable to new versions of viruses. Researcher Abdelhamid Naseri compared it to an old UnDefend vulnerability he reported in April 2026.
A vulnerability found in Windows allows you to completely disable built-in antivirus updates. This was reported by BleepingComputer.
The problem was brought to the attention of security researcher Abdelhamid Naseri. He found out that with the help of a new exploit called BigDiskBuster, attackers learned to deceive the Windows Defender antivirus built into the operating system (OS). The vulnerability discovered by Abdelhamid allows one to disable updates to security program databases.
The specialist said that when BigDiskBuster is activated, Windows Defender actually “forgets” that it needs to update the virus databases. The material says that while the exploit does not work perfectly and requires improvement, but the main mechanism for blocking updates is already functioning.
Abdelhamid Naseri noted that this problem makes computers vulnerable to attacks by new versions of viruses. He also emphasized that the system flaw is associated with all current versions of the Microsoft OS. The researcher compared the new BigDiskBuster vulnerability with the old UnDefend, which he talked about in April 2026. It also made it possible to block updates to anti-virus databases.
What to Watch
AI outlook — possibilities, not facts
Microsoft will release a security update to address the BigDiskBuster vulnerability in the coming weeks
Likely · Within weeks
Open Questions
- When does Microsoft plan to release a patch for the BigDiskBuster vulnerability?
- How widespread is this vulnerability among Windows users currently?
- Does operating BigDiskBuster require administrator rights or physical access to the device?
