---
id: CVE-2025-40078
title: 'bpf: Explicitly check accesses to bpf_sock_addr'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Explicitly check accesses to bpf_sock_addr

  Syzkaller found a kernel warning on the following sock_addr program:

      0: r0 = 0
      1: r2 = *(u32 *)(r1 +60)
      2:…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    de44cdc50d2dce8718cb57deddf9cf1be9a7759f
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    76e04bbb4296fb6eac084dbfc27e02ccc744db3e
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    6d8b1a21fd5c34622b0c3893c61e4a38d8ba53ec
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    4f00858cd9bbbdf67159e28b85a8ca9e77c83622
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    cdeafacb4f9ff261a96baef519e29480fd7b1019
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    fe9d33f0470350558cb08cecb54cf2267b3a45d2
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    ad8b4fe5617e3c85fc23267f02500c4f3bf0ff69
  - >-
    Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 <
    6fabca2fc94d33cdf7ec102058983b086293395f
  - Linux 4.18
published: '2025-10-28'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T08:42:46.488Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-40078'
references:
  - url: 'https://git.kernel.org/stable/c/de44cdc50d2dce8718cb57deddf9cf1be9a7759f'
  - url: 'https://git.kernel.org/stable/c/76e04bbb4296fb6eac084dbfc27e02ccc744db3e'
  - url: 'https://git.kernel.org/stable/c/6d8b1a21fd5c34622b0c3893c61e4a38d8ba53ec'
  - url: 'https://git.kernel.org/stable/c/4f00858cd9bbbdf67159e28b85a8ca9e77c83622'
  - url: 'https://git.kernel.org/stable/c/cdeafacb4f9ff261a96baef519e29480fd7b1019'
  - url: 'https://git.kernel.org/stable/c/fe9d33f0470350558cb08cecb54cf2267b3a45d2'
  - url: 'https://git.kernel.org/stable/c/ad8b4fe5617e3c85fc23267f02500c4f3bf0ff69'
  - url: 'https://git.kernel.org/stable/c/6fabca2fc94d33cdf7ec102058983b086293395f'
tags:
  - cve.org
epss: 0.00222
epssPercentile: 0.11557
ingestedAt: '2026-09-08T15:33:26.996Z'
---

## Overview

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

bpf: Explicitly check accesses to bpf_sock_addr

Syzkaller found a kernel warning on the following sock_addr program:

    0: r0 = 0
    1: r2 = *(u32 *)(r1 +60)
    2: exit

which triggers:

    verifier bug: error during ctx access conversion (0)

This is happening because offset 60 in bpf_sock_addr corresponds to an
implicit padding of 4 bytes, right after msg_src_ip4. Access to this
padding isn't rejected in sock_addr_is_valid_access and it thus later
fails to convert the access.

This patch fixes it by explicitly checking the various fields of
bpf_sock_addr in sock_addr_is_valid_access.

I checked the other ctx structures and is_valid_access functions and
didn't find any other similar cases. Other cases of (properly handled)
padding are covered in new tests in a subsequent patch.

## Affected

- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < de44cdc50d2dce8718cb57deddf9cf1be9a7759f`
- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < 76e04bbb4296fb6eac084dbfc27e02ccc744db3e`
- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < 6d8b1a21fd5c34622b0c3893c61e4a38d8ba53ec`
- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < 4f00858cd9bbbdf67159e28b85a8ca9e77c83622`
- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < cdeafacb4f9ff261a96baef519e29480fd7b1019`
- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < fe9d33f0470350558cb08cecb54cf2267b3a45d2`
- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < ad8b4fe5617e3c85fc23267f02500c4f3bf0ff69`
- `Linux >= 1cedee13d25ab118d325f95588c1a084e9317229 < 6fabca2fc94d33cdf7ec102058983b086293395f`
- `Linux 4.18`

## Remediation

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