CVE-2026-53219

In the Linux kernel, the following vulnerability has been resolved:

netfilter: x_tables: avoid leaking percpu counter pointers

The native and compat get-entries paths copy the fixed rule entry header

from the kernelized rule blob to userspace before overwriting the entry's

counter fields with a sanitized counter snapshot.

On SMP kernels, entry->counters.pcnt contains the percpu allocation

address used by x_tables rule counters. A caller can provide a userspace

buffer that faults during the initial fixed-header copy after pcnt has

been copied but before the later sanitized counter copy runs. The syscall

then returns -EFAULT while leaving the raw percpu pointer in userspace.

Copy only the fixed entry prefix before counters from the kernelized rule

blob, then copy the sanitized counter snapshot into the counter field.

Apply this ordering to the IPv4, IPv6, and ARP native and compat

get-entries implementations so a fault cannot expose the internal percpu

counter pointer.