Kernel Vulnerability in Linux Affecting SMB2 Operations

CVE-2026-53271

What is CVE-2026-53271?

A vulnerability in the Linux kernel exists due to the mishandling of opinfo->conn during oplock and lease break notifications in the ksmbd module. When smb2_oplock_break_noti() and smb2_lease_break_noti() access opinfo->conn without performing necessary checks, it poses a risk of dereferencing a NULL pointer. This can occur in a race condition scenario where a concurrent SMB2 LOGOFF might set op->conn to NULL, leading to a potential crash or undefined behavior. The resolution involves implementing READ_ONCE() for the reads of opinfo->conn and returning early if it is NULL, which helps to mitigate the risk of remote exploitation.

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