CVE-2026-53219 netfilter: x_tables: avoid leaking percpu counter pointers
A local attacker can leak internal percpu counter pointers from the Linux kernel netfilter subsystem by triggering a fault during rule entry retrieval.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53219?
CVE-2026-53219 is a medium-severity vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-53219?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53219?
Apply the vendor's patch.
Is CVE-2026-53219 being exploited?
There is no known exploitation of CVE-2026-53219 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90446, BELL-CVE-2026-53219, DEBIAN-CVE-2026-53219, GHSA-gv3c-2ghh-53g2, ROOT-OS-DEBIAN-11-CVE-2026-53219, ROOT-OS-DEBIAN-12-CVE-2026-53219 and 3 more.