R. Diez

**Name of the Vulnerable Software and Affected Versions** Linux kernel versions 6.3 and earlier **Description** The issue is related to a regression in the Linux kernel's handling of non-standard maximum write sizes when using the SMB protocol. This regression was introduced by the conversion to netfs in the 6.3 kernel. When the maximum write size is set to a value that is not a multiple of 4096, the netfs code can skip the end of the final page during large sequential writes, resulting in data corruption. To mitigate this, a warning is added when a user specifies a non-standard maximum write size, and the maximum write size is rounded down to the nearest multiple of 4096. **Recommendations** For Linux kernel version 6.3 and earlier, consider updating to a newer version that includes the fix for this regression. As a temporary workaround, avoid setting non-standard maximum write sizes by ensuring the `wsize` mount parameter is a multiple of 4096. If a non-standard maximum write size is required, be aware of the potential for data corruption and take necessary precautions to mitigate this risk.