CVE-2022-49450: 
Linux Kernel vulnerability analysis and mitigation

CVE-2022-49450 is a vulnerability in the Linux kernel's AF_RXRPC implementation, specifically related to the listen() handler functionality. The vulnerability was discovered in 2022 and publicly disclosed in February 2025. The issue affects the Linux kernel's network stack, particularly the RXRPC protocol implementation (Kernel Git).

The vulnerability occurs in the AF_RXRPC's listen() handler, which allows setting the backlog up to 32 (through sysctl configuration). While the preallocation circular buffers have 32 slots, one slot must remain empty due to the CIRC_CNT() implementation. When listen(rxrpc_sock, 32) is called, it causes an oops condition during socket closure because rxrpc_service_prealloc_one() allocates one too many calls, and rxrpc_discard_prealloc() fails to clear them, believing the ring is empty (Kernel Git).

When exploited, the vulnerability results in a kernel NULL pointer dereference at address 0x86. This occurs when rxrpc_release_calls_on_socket() attempts to abort calls with an unset call->peer pointer, leading to a kernel oops condition that could potentially crash the system (NVD).

The vulnerability is triggered through normal system operations when using specific socket configurations, particularly when setting the maximum backlog value to 32. The issue manifests during socket closure operations, making it a reliability concern rather than a direct security exploit (Kernel Git).

The fix involves modifying the maximum backlog value to RXRPC_BACKLOG_MAX - 1 to match the actual ring capacity. This change has been implemented in the kernel source through a patch that adjusts the sysctl configuration limits (Kernel Git).