zero-copy page pinning

Zero-copy page pinning is a kernel memory management technique used in networking subsystems like Linux Reliable Datagram Sockets (RDS). It allows data to be transferred directly between user space and network buffers without copying, improving performance. However, a failed zero-copy page-pin operation can leave stale accounting state, leading to a double-free vulnerability. This issue is tracked as CVE-2026-43494 and is associated with a local privilege-escalation technique called PinTheft. The vulnerability affects Linux servers, WSL-adjacent development environments, and containers. Mitigations include applying kernel patches and monitoring for unusual memory or network behavior. Administrators should prioritize updates to prevent exploitation.