Linux Kernel CVE-2026-43463

The affected components are the rxrpc subsystem (Reliable RPC over UDP, used as the transport for the AFS distributed filesystem client in the Linux kernel) and the afs subsystem (Andrew File System). The root cause, classified as CWE-476 (NULL Pointer Dereference), is a broader error-handling defect: rxrpc_kernel_lookup_peer() was documented to return NULL on allocation failure, but could also return an ERR_PTR-encoded error value. Callers in the afs subsystem used only a simple NULL check rather than the kernel's IS_ERR() / PTR_ERR() idiom, meaning non-NULL error pointers were treated as valid peer object pointers and subsequently dereferenced. The fix has two components: (1) normalizing rxrpc_kernel_lookup_peer() to return -ENOMEM (via ERR_PTR) rather than NULL on allocation failure, and (2) updating all afs callers to use IS_ERR() and PTR_ERR() for proper error propagation. CPE: cpe:2.3:a:linux:linux:*:*:*:*:*:*:*:*.