CVE-2026-53383
Description
A flaw was found in the Linux kernel's ksmbd component. A remote attacker can trigger a NULL pointer dereference by sending a specially crafted compound SMB2 request. This occurs because the session validation logic for non-first operations in a compound request does not properly check the session state, allowing a tree connect operation to proceed with an invalid session. Successful exploitation leads to a kernel crash, causing a denial of service for all ksmbd clients.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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