Full Report
Microsoft says a known issue that reverts mouse settings after installing the KB5120998 August 2026 preview update affects only non-English Windows 11 systems. [...]
Analysis Summary
# Vulnerability: KB5120998 Mouse Settings Reset Bug
## CVE Details
- **CVE ID**: N/A (Functional Regression/Bug)
- **CVSS Score**: N/A (Low Availability Impact)
- **CWE**: CWE-755: Improper Handling of Exceptional Conditions / Localization Error
## Affected Systems
- **Products**: Microsoft Windows 11
- **Versions**: Versions 25H2 and 24H2
- **Configurations**: Systems using **non-English** installation locales/languages.
## Vulnerability Description
Following the installation of the KB5120998 preview update, a bug in the code components used for non-English Windows installations causes mouse personalization settings to fail to load. This technical flaw results in the system defaulting to standard cursor and cursor animation settings. Affected users report that they are unable to restore their custom settings manually after the reset occurs.
## Exploitation
- **Status**: Not exploited (Functional bug)
- **Complexity**: N/A
- **Attack Vector**: N/A
## Impact
- **Confidentiality**: None
- **Integrity**: Low (Reversion of user-defined UI preferences)
- **Availability**: Low (Loss of accessibility/personalization features; potential impact on productivity)
## Remediation
### Patches
- As of the latest report, Microsoft has acknowledged the issue but has not yet released a formal cumulative fix. Users are advised to monitor the Windows Release Health dashboard for a forthcoming resolution.
### Workarounds
- **Avoid Installation**: Since KB5120998 is an optional non-security preview update, users can choose not to install it.
- **Update Settings**: Disable the "Get the latest updates as soon as they're available" toggle in Windows Update to prevent automatic installation of preview builds.
- **Rollback**: Users experiencing the issue can uninstall the KB5120998 update via *Settings > Windows Update > Update history > Uninstall updates*.
## Detection
- **Indicators of compromise**: Not applicable.
- **Detection methods**: Manual verification of mouse cursor schemes and animations in the *Mouse Properties* menu. Check for the presence of Update ID **KB5120998** on non-English Windows 11 systems.
## References
- Microsoft Windows Release Health Dashboard: hxxps[://]learn[.]microsoft[.]com/en-us/windows/release-health/status-windows-11-24h2#mouse-customization-is-reset-on-non-english-windows-devices
- BleepingComputer Advisory: hxxps[://]www[.]bleepingcomputer[.]com/news/microsoft/microsoft-kb5120998-mouse-reset-bug-affects-only-non-english-pcs/