SMB2 Vulnerability in Linux Kernel Affecting Multiple Versions

CVE-2026-99275

What is CVE-2026-99275?

A vulnerability has been identified in the SMB2 handling of the Linux kernel, where the smb2_check_message() function erroneously accepts short SESSION_SETUP responses when the SMB2 status is non-zero. This flaw allows potentially malicious content to be read from stale data in a reused buffer, posing a risk of buffer overflow during NTLMv2 authentication challenges. Specifically, if an attacker crafts a SESSION_SETUP response under certain conditions, the unvalidated reading of the SecurityBufferLength could lead to significant security risks, including unauthorized data exposure. It is crucial to apply the latest patches to mitigate these vulnerabilities.

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