CVE-2026-43050 is a use-after-free vulnerability in the Linux kernel's ATM LEC module caused by a race condition between lec_atm_close() clearing a pointer and concurrent access to it. This flaw can lead to accessing freed memory in sock_def_readable(), potentially causing system instability or crashes. The issue is fixed by converting the pointer to an RCU-protected pointer with proper synchronization to prevent concurrent access after freeing.