Microsoft resolves Windows Defender crash issue following security update
Bug causing 0xc0000005 access violation errors addressed in latest update cycle
Key Takeaways
- Microsoft fixed a Windows Defender crash bug causing 0xc0000005 errors after a security update.
- The issue could disable real-time protection on affected systems.
- No active exploitation has been reported; the bug was triggered by the update itself.
- Users should apply the latest Windows updates to resolve the issue.
Quick answers
- What happened?
- Microsoft has released a fix for a bug that caused Windows Defender to crash on certain systems after a recent security update. The issue resulted in 0xc0000005 access violation errors, potentially leaving systems without real-time protection. The company has not reported active exploitation of the bug.
- Which products are affected?
- Windows Defender
- What should defenders do?
- Users should ensure their systems are running the latest Windows updates. Microsoft has released a fix; applying the update should restore Windows Defender functionality.
Microsoft has addressed a known issue affecting Windows Defender that caused the security tool to crash following a recent security update. Affected users experienced 0xc0000005 access violation errors, which could disable real-time protection and leave systems exposed to threats. The bug was triggered by the update and not by active exploitation in the wild. Microsoft has released a resolution, and users are advised to ensure their systems are running the latest updates to restore full functionality. No specific CVE identifier has been assigned to this issue at this time.
Security Details
The bug caused Windows Defender to crash with 0xc0000005 access violation errors on some systems after a recent security update. The issue was triggered by the update and not by active exploitation.
Affected products
Windows Defender
Mitigation
Users should ensure their systems are running the latest Windows updates. Microsoft has released a fix; applying the update should restore Windows Defender functionality.
Sources
BleepingComputer
Microsoft fixes known issue causing Windows Defender crashes
Aug 19, 2026 · 11:14
Original link
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