Windows Antivirus | August 2026 | Platform 4.18.26080.3 | Engine 1.1.26080.3
Analysis / inference: Microsoft released Defender Antivirus platform version 4.18.26080.3 and engine version 1.1.26080.3 with new health monitoring, hardening fixes, and bug resolutions.
- Dates
- Source and collection dates not recorded
- Source
- Microsoft Defender for Endpoint releases · Limited verification
- Classification
- Microsoft Security
Section 01 · Summary analysis
Microsoft released platform version 4.18.26080.3 and engine version 1.1.26080.3, adding Cisco Umbrella health monitoring for Network Protection, hardening network authentication credential exposure, and fixing BitLocker state detection, disk I/O cleanup failures, and ASR prompt behaviors.
AI summary / analysis; claims are not independently verified. Check the primary source before acting.
Section 02 · Analysis
SecOps Signal analysisThis monthly update fixes platform bugs, improves disk I/O handling, hardens credential protection, and introduces Cisco Umbrella health monitoring for Network Protection.
Improves stability by resolving disk I/O issues, stuck staging folder updates, and incorrect AMSI path exclusions, while enhancing network protection visibility with Cisco Umbrella.
Section 03 · Recommended actions
- Ensure automatic update channels for Microsoft Defender Antivirus receive platform version 4.18.26080.3 and engine version 1.1.26080.3.
- Review network protection and ASR configurations in environments utilizing Cisco Umbrella or custom AMSI path exclusions.
- Verify that Windows Defender Antivirus platform version 4.18.26080.3 and engine version 1.1.26080.3 are rolling out or installed successfully across endpoints.
- Check environment logs for previous disk I/O spikes related to shared signature root locations containing whitespace.