Full Report
Microsoft has confirmed a known issue that is preventing users from quitting the Windows 11 Task Manager after installing the October 2025 optional update. [...]
Analysis Summary
# Vulnerability: Windows Task Manager Fails to Terminate After Optional Update
## CVE Details
- CVE ID: N/A (This is a known issue documented by the vendor, not a publicly disclosed, tracked CVE at the time of the report.)
- CVSS Score: N/A
- CWE: N/A
## Affected Systems
- Products: Windows 11
- Versions: Systems that have installed the October 2025 optional update, specifically KB5067036.
- Configurations: Relevant across affected Windows 11 feature updates (e.g., 25H2 mentioned in context).
## Vulnerability Description
After installing the October 2025 optional update (KB5067036), closing the Task Manager application via the 'X' button does not fully terminate the `taskmgr.exe` process. This results in multiple lingering instances of `taskmgr.exe` running in the background, consuming system resources and potentially causing noticeable system slowdowns, stuttering, and CPU hangs, especially when many instances accumulate.
## Exploitation
- Status: Not related to external exploitation; this is a configuration/logic bug introduced by the update.
- Complexity: N/A (Internal process management failure)
- Attack Vector: N/A
## Impact
- Confidentiality: None/Minimal (Local system operation impact only)
- Integrity: Low (System stability and performance degradation)
- Availability: Medium (Degraded device performance)
## Remediation
### Patches
- Status: Microsoft is currently investigating; **No official patch is available at the time of this advisory.**
### Workarounds
Users who have installed KB5067036 can use the following methods to stop the lingering processes:
1. **Manual Termination:** Open Task Manager, find the lingering "Task Manager" instances in the Processes or Details tab, and manually click "End Task" for each one.
2. **Command Line Force Kill:** Run Command Prompt as Administrator and execute the following command to forcibly terminate all running `taskmgr.exe` instances:
taskkill.exe /im taskmgr.exe /f
## Detection
- Indicators of compromise: Noticeable system slowdowns or stuttering occurring after installing KB5067036.
- Detection methods and tools: Monitoring the Processes tab in Task Manager for an unusually high count of `taskmgr.exe` processes running, even when the Task Manager UI is closed. This is visible as multiple entries named "Task Manager" or "Taskmgr.exe".
## References
- Vendor Advisory (Microsoft Release Health): hXXps://learn.microsoft.com/en-us/windows/release-health/status-windows-11-25h2#task-manager-process-might-continue-to-run-in-background-after-app-is-closed
- KB Article for the Update: KB5067036