---
id: CVE-2026-31671
title: 'xfrm_user: fix info leak in build_report()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xfrm_user: fix info leak in build_report()

  struct xfrm_user_report is a __u8 proto field followed by a struct
  xfrm_selector which means there is three "empty" bytes of…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    d27c02eec529f78055a46a5c9e6c62684382b2d8
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    716c546e88cfe49d841658240e10cb57bc50a2cc
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    0616314b3b34f24cbb91da8c6bd8bcdc4c8592f9
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    e0c8542c3d097ed4205ded51868195d5d6ddac62
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    ff5ee507302303b15859753c3e0d67d38fd12c88
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    6c55714c931051cd7f4839c19ce0867179fd22fe
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    0a30dceb0e1f0c480d2482e6d7cebf8aebb6eb72
  - >-
    Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 <
    d10119968d0e1f2b669604baf2a8b5fdb72fa6b4
  - Linux 2.6.19
published: '2026-04-24'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T08:48:02.229Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-31671'
references:
  - url: 'https://git.kernel.org/stable/c/d27c02eec529f78055a46a5c9e6c62684382b2d8'
  - url: 'https://git.kernel.org/stable/c/716c546e88cfe49d841658240e10cb57bc50a2cc'
  - url: 'https://git.kernel.org/stable/c/0616314b3b34f24cbb91da8c6bd8bcdc4c8592f9'
  - url: 'https://git.kernel.org/stable/c/e0c8542c3d097ed4205ded51868195d5d6ddac62'
  - url: 'https://git.kernel.org/stable/c/ff5ee507302303b15859753c3e0d67d38fd12c88'
  - url: 'https://git.kernel.org/stable/c/6c55714c931051cd7f4839c19ce0867179fd22fe'
  - url: 'https://git.kernel.org/stable/c/0a30dceb0e1f0c480d2482e6d7cebf8aebb6eb72'
  - url: 'https://git.kernel.org/stable/c/d10119968d0e1f2b669604baf2a8b5fdb72fa6b4'
tags:
  - cve.org
epss: 0.00171
epssPercentile: 0.05678
ingestedAt: '2026-09-08T15:33:26.989Z'
---

## Overview

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

xfrm_user: fix info leak in build_report()

struct xfrm_user_report is a __u8 proto field followed by a struct
xfrm_selector which means there is three "empty" bytes of padding, but
the padding is never zeroed before copying to userspace.  Fix that up by
zeroing the structure before setting individual member variables.

## Affected

- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < d27c02eec529f78055a46a5c9e6c62684382b2d8`
- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < 716c546e88cfe49d841658240e10cb57bc50a2cc`
- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < 0616314b3b34f24cbb91da8c6bd8bcdc4c8592f9`
- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < e0c8542c3d097ed4205ded51868195d5d6ddac62`
- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < ff5ee507302303b15859753c3e0d67d38fd12c88`
- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < 6c55714c931051cd7f4839c19ce0867179fd22fe`
- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < 0a30dceb0e1f0c480d2482e6d7cebf8aebb6eb72`
- `Linux >= 97a64b4577ae2bc5599dbd008a3cd9e25de9b9f5 < d10119968d0e1f2b669604baf2a8b5fdb72fa6b4`
- `Linux 2.6.19`

## Remediation

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