The flaw concerns incorrect handling of lease breaks and acknowledgment states in the ksmbd SMB2 server component of the Linux kernel. When a client requests a lease break, the server must acknowledge only a subset of the target state as defined by the SMB2 protocol. The patch corrects logic that allowed the server to partially enforce this rule, meaning a malicious SMB client could send an acknowledgment that does not obey the subset constraint. This could cause the server to transition to an invalid lease state, leading to data inconsistencies, denied writes or a denial of service if the client repeatedly requests improper leases.

The flaw is present in all Linux kernel releases that include ksmbd. No specific version bounds were supplied, so every distribution shipping a kernel that contains ksmbd before the patch is potentially affected. This covers both generic Linux systems and any services that rely on the kernel’s SMB server capabilities.

No CVSS or EPSS score is published, and the vulnerability is not listed in KEV. Based on the absence of public exploitation data, the risk appears low. However, an attacker could exploit the flaw by sending crafted SMB2 lease break acknowledgments that violate the subset rule defined by the protocol. This would require direct SMB traffic to the ksmbd service and could lead to denial of service or data inconsistency, representing a moderate but protocol‑specific risk.