---
id: CVE-2026-31428
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

  __build_packet_message() manually constructs the NFULA_PAYLOAD netlink
  attribute using skb_pu…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

  __build_packet_message() manually constructs the NFULA_PAYLOAD netlink
  attribute using skb_pu…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-908
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 2.6.24, < 5.10.253'
  - 'linux_kernel >= 5.11, < 5.15.203'
  - 'linux_kernel >= 5.16, < 6.1.168'
  - 'linux_kernel >= 6.2, < 6.6.131'
  - 'linux_kernel >= 6.7, < 6.12.80'
  - 'linux_kernel >= 6.13, < 6.18.21'
  - 'linux_kernel >= 6.19, < 6.19.11'
  - linux_kernel = 7.0
patched:
  - linux_kernel 6.19.11
published: '2026-04-13'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:04.760'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31428'
references:
  - url: 'https://git.kernel.org/stable/c/21d8efda029948d3666b0db5afcc0d36c0984aae'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7eff72968161fb8ddb26113344de3b92fb7d7ef5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7f3e5d72455936f42709116fabeca3bb216cda62'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a2f6ff3444b663d6cfa63eadd61327a18592885a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a8365d1064ded323797c5e28e91070c52f44b76c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c9f6c51d36482805ac3ffadb9663fe775a13e926'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fc961dd7272b5e4a462999635e44a4770d7f2482'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-082556.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-457936.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00131
epssPercentile: 0.02657
ingestedAt: '2026-09-08T15:33:26.990Z'
---

## Overview

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

netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

__build_packet_message() manually constructs the NFULA_PAYLOAD netlink
attribute using skb_put() and skb_copy_bits(), bypassing the standard
nla_reserve()/nla_put() helpers. While nla_total_size(data_len) bytes
are allocated (including NLA alignment padding), only data_len bytes
of actual packet data are copied. The trailing nla_padlen(data_len)
bytes (1-3 when data_len is not 4-byte aligned) are never initialized,
leaking stale heap contents to userspace via the NFLOG netlink socket.

Replace the manual attribute construction with nla_reserve(), which
handles the tailroom check, header setup, and padding zeroing via
__nla_reserve(). The subsequent skb_copy_bits() fills in the payload
data on top of the properly initialized attribute.

## Affected

- `linux_kernel >= 2.6.24, < 5.10.253`
- `linux_kernel >= 5.11, < 5.15.203`
- `linux_kernel >= 5.16, < 6.1.168`
- `linux_kernel >= 6.2, < 6.6.131`
- `linux_kernel >= 6.7, < 6.12.80`
- `linux_kernel >= 6.13, < 6.18.21`
- `linux_kernel >= 6.19, < 6.19.11`
- `linux_kernel = 7.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.11`