Linux Kernel Vulnerability Affects RXRPC ACKALL Packet Handling

CVE-2026-74430

What is CVE-2026-74430?

A vulnerability in the Linux kernel's RXRPC packet handling can lead to null-pointer dereference due to improper ACKALL packet processing. The function 'rxrpc_input_ackall()' allows forged ACKALL packets to pass through without validating the state of the call, potentially leading to a situation where no transmit buffers exist. This issue can occur in the RXRPC_CALL_SERVER_RECV_REQUEST state, resulting in application crashes or instability. The resolution involves introducing new call states to ensure that ACKALL packets are only processed when they are valid and making appropriate checks to prevent null dereference.

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