---
id: CVE-2025-38162
title: 'netfilter: nft_set_pipapo: prevent overflow in lookup table allocation'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfilter: nft_set_pipapo: prevent overflow in lookup table allocation

  When calculating the lookup table size, ensure the following
  multiplication does not overflow:

  …
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da <
    91edc076439c9e2f34b176149f1c84a47a8ec32f
  - >-
    Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da <
    a9e757473561da93c6a4136f0e59aba91ec777fc
  - >-
    Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da <
    c1360ac8156c0a3f2385baef91d8d26fd9d39701
  - >-
    Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da <
    43fe1181f738295624696ae9ff611790edb65b5e
  - >-
    Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da <
    4c5c6aa9967dbe55bd017bb509885928d0f31206
  - Linux 5.6
published: '2025-07-03'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T08:41:44.717Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-38162'
references:
  - url: 'https://git.kernel.org/stable/c/91edc076439c9e2f34b176149f1c84a47a8ec32f'
  - url: 'https://git.kernel.org/stable/c/a9e757473561da93c6a4136f0e59aba91ec777fc'
  - url: 'https://git.kernel.org/stable/c/c1360ac8156c0a3f2385baef91d8d26fd9d39701'
  - url: 'https://git.kernel.org/stable/c/43fe1181f738295624696ae9ff611790edb65b5e'
  - url: 'https://git.kernel.org/stable/c/4c5c6aa9967dbe55bd017bb509885928d0f31206'
tags:
  - cve.org
epss: 0.00165
epssPercentile: 0.05064
ingestedAt: '2026-09-08T15:33:26.997Z'
---

## Overview

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

netfilter: nft_set_pipapo: prevent overflow in lookup table allocation

When calculating the lookup table size, ensure the following
multiplication does not overflow:

- desc->field_len[] maximum value is U8_MAX multiplied by
  NFT_PIPAPO_GROUPS_PER_BYTE(f) that can be 2, worst case.
- NFT_PIPAPO_BUCKETS(f->bb) is 2^8, worst case.
- sizeof(unsigned long), from sizeof(*f->lt), lt in
  struct nft_pipapo_field.

Then, use check_mul_overflow() to multiply by bucket size and then use
check_add_overflow() to the alignment for avx2 (if needed). Finally, add
lt_size_check_overflow() helper and use it to consolidate this.

While at it, replace leftover allocation using the GFP_KERNEL to
GFP_KERNEL_ACCOUNT for consistency, in pipapo_resize().

## Affected

- `Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da < 91edc076439c9e2f34b176149f1c84a47a8ec32f`
- `Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da < a9e757473561da93c6a4136f0e59aba91ec777fc`
- `Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da < c1360ac8156c0a3f2385baef91d8d26fd9d39701`
- `Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da < 43fe1181f738295624696ae9ff611790edb65b5e`
- `Linux >= 3c4287f62044a90e73a561aa05fc46e62da173da < 4c5c6aa9967dbe55bd017bb509885928d0f31206`
- `Linux 5.6`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.