Use-After-Free Vulnerability in Linux Kernel's ksmbd Component

CVE-2026-31718

What is CVE-2026-31718?

A vulnerability exists in the Linux kernel's ksmbd component, which can lead to a use-after-free situation. When a durable file handle persists across a session disconnect, the system may improperly manage byte-range locks associated with that file handle. Specifically, when the durable scavenger attempts to close the file descriptor after a timeout, it fails to correctly handle the cleanup of dangling lock entries due to improper asymmetrical cleanup processes. This issue arises when the connection object is freed while lock entries remain linked to an invalid reference, potentially leading to undefined behavior and memory corruption.

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