CVE-2026-53219 is a vulnerability in the Linux kernel netfilter x_tables component where the native and compat get-entries paths improperly handle copying of rule entry headers and counters. On SMP kernels, the entry->counters.pcnt field contains a percpu allocation address. If a userspace buffer faults after this pointer is copied but before sanitized counters overwrite it, the syscall returns an error but leaves the raw percpu pointer exposed in userspace memory. The fix involves copying only the fixed entry prefix before counters first, then copying sanitized counter snapshots, preventing exposure of internal percpu pointers across IPv4, IPv6, and ARP implementations.

The vulnerability does not affect confidentiality or integrity but can cause availability issues by returning an error (-EFAULT) during syscall execution. It may leak kernel percpu counter pointers to userspace, which could aid in further kernel attacks or information disclosure in some scenarios, though no direct confidentiality impact is reported. There are no known exploits in the wild.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The description indicates the vulnerability has been resolved in the Linux kernel, but no explicit patch links or fixed versions are provided. Users should monitor official Linux kernel advisories and update to fixed kernel versions once available.