Full Report
Microsoft has resolved a known issue preventing users from quitting the Windows 11 Task Manager after installing the optional Windows 11 KB5067036 update. [...]
Analysis Summary
# Vulnerability: Windows 11 Task Manager Fails to Terminate After KB5067036 Update
## CVE Details
- CVE ID: Not explicitly provided in the text. (This is a post-patch functional bug report, not a security vulnerability with a formal CVE listed.)
- CVSS Score: Not applicable/Not provided. (Issue is functional/performance degradation, not a traditional security vulnerability.)
- CWE: Not applicable/Not provided.
## Affected Systems
- Products: Windows 11
- Versions: Systems that installed the optional Windows 11 KB5067036 update (released on or after October 28, 2025).
- Configurations: Systems where the user attempted to close the Task Manager via the 'X' close button.
## Vulnerability Description
After installing update KB5067036, closing the Windows 11 Task Manager (taskmgr.exe) via the 'X' button did not fully terminate the process. This resulted in multiple lingering instances of `taskmgr.exe` running invisibly in the background. These background processes consumed system resources, leading to noticeable performance degradation, stuttering, and CPU hangs in other applications.
## Exploitation
- Status: Not exploited (Described as a functional bug causing performance issues).
- Complexity: Not applicable.
- Attack Vector: Not applicable (Internal system function failure).
## Impact
- Confidentiality: Minimal/None (Unless resource exhaustion leads to broader system instability).
- Integrity: Negligible (Primarily performance-related).
- Availability: Moderate (Degraded system performance and responsiveness due to CPU/resource utilization by lingering processes).
## Remediation
### Patches
- **KB5068861:** The November Windows security update resolves this issue.
### Workarounds
1. **Manual Termination:** Wait for the KB5068861 update. If unable to install immediately, users can manually quit the background Task Manager processes.
2. **Command Line Fix:** Use the Command Prompt (run as administrator) to force termination of all Task Manager instances using the following command:
`taskkill.exe /im taskmgr.exe /f`
## Detection
- Indicators of compromise: Unexplained system slowdowns, stuttering, or CPU hangs, especially after updating with KB5067036. Frequent background process monitoring showing high usage by multiple `taskmgr.exe` instances when the Task Manager window is not visible.
- Detection methods and tools: Monitoring system resource usage, particularly CPU consumption, and examining running processes for multiple instances of `taskmgr.exe`.
## References
- Microsoft Advisory (Related to initial acknowledgment): hxxps://www.bleepingcomputer.com/news/microsoft/microsoft-windows-task-manager-wont-quit-after-kb5067036-update/
- Fix Update Reference: hxxps://support.microsoft.com/help/5068861