CVE-2026-64401

A flaw was found in the Linux kernel's Server Message Block (SMB) client. This vulnerability, a use-after-free, occurs when handling witness registrations. Specifically, a second mount for the same network share can cause the system to incorrectly reference a previously freed connection, leading to a use-after-free condition. This can result in system instability or potentially more severe impacts.

This vulnerability is evaluated with a Moderate impact for Red Hat environments because exploiting this flaw requires local access and complex timing to trigger concurrent mounts against a share utilizing the Server Witness Protocol (SWN). The risk is bounded because the issue does not permit unauthenticated remote exploitation and depends on non-default witness notification features. Additionally, the vulnerable code is not present in Red Hat Enterprise Linux kernels, leaving standard product deployments unaffected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.