# 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.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 25 Jun 2026
- **Updated:** 15 Oct 2026
- **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, ROOT-OS-UBUNTU-2204-CVE-2026-53219, ROOT-OS-UBUNTU-2404-CVE-2026-53219, UBUNTU-CVE-2026-53219

## 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: 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

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53219 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-53219 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53219/ (Markdown: https://insights.sbomify.com/CVE-2026-53219/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53219
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53219
- OSV: https://osv.dev/vulnerability/CVE-2026-53219

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53219/
Summaries are generated and may contain mistakes; the official description above is the record.