---
id: CVE-2025-39965
title: 'xfrm: xfrm_alloc_spi shouldn''t use 0 as SPI'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xfrm: xfrm_alloc_spi shouldn't use 0 as SPI

  x->id.spi == 0 means "no SPI assigned", but since commit
  94f39804d891 ("xfrm: Duplicate SPI Handling"), we now create state…
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 >= 3d8090bb53424432fa788fe9a49e8ceca74f0544 <
    0baf92d0b1590b903c1f4ead75e61715e50e8146
  - >-
    Linux >= 2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38 <
    9fcedabaae0096f712bbb4ccca6a8538af1cd1c8
  - >-
    Linux >= 29e9158f91f99057dbd35db5e8674d93b38549fe <
    a78e55776522373c446f18d5002a8de4b09e6bf7
  - >-
    Linux >= 94f39804d891cffe4ce17737d295f3b195bc7299 <
    cd8ae32e4e4652db55bce6b9c79267d8946765a9
  - Linux fb58962aa3b9359988c7b5b15a971fd9ad5b0ecd
  - Linux c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47
  - Linux >= 6.1.191 < 6.2
  - Linux >= 6.15.11 < 6.16
  - Linux >= 6.6.103 < 6.6.109
  - Linux >= 6.12.43 < 6.12.50
  - Linux >= 6.16.2 < 6.16.10
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:55:18.566568Z'
exploitAvailable: true
published: '2025-10-13'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:22:40.645Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-39965'
references:
  - url: 'https://git.kernel.org/stable/c/0baf92d0b1590b903c1f4ead75e61715e50e8146'
  - url: 'https://git.kernel.org/stable/c/9fcedabaae0096f712bbb4ccca6a8538af1cd1c8'
  - url: 'https://git.kernel.org/stable/c/a78e55776522373c446f18d5002a8de4b09e6bf7'
  - url: 'https://git.kernel.org/stable/c/cd8ae32e4e4652db55bce6b9c79267d8946765a9'
tags:
  - cve.org
  - exploit-available
epss: 0.00199
epssPercentile: 0.09842
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/Shreyas-Penkar/CVE-2025-39965'
  checkedAt: '2026-11-03T21:56:27.345Z'
ingestedAt: '2026-10-15T22:48:25.533Z'
---

## Overview

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

xfrm: xfrm_alloc_spi shouldn't use 0 as SPI

x->id.spi == 0 means "no SPI assigned", but since commit
94f39804d891 ("xfrm: Duplicate SPI Handling"), we now create states
and add them to the byspi list with this value.

__xfrm_state_delete doesn't remove those states from the byspi list,
since they shouldn't be there, and this shows up as a UAF the next
time we go through the byspi list.

## Affected

- `Linux >= 3d8090bb53424432fa788fe9a49e8ceca74f0544 < 0baf92d0b1590b903c1f4ead75e61715e50e8146`
- `Linux >= 2fc5b54368a1bf1d2d74b4d3b8eea5309a653e38 < 9fcedabaae0096f712bbb4ccca6a8538af1cd1c8`
- `Linux >= 29e9158f91f99057dbd35db5e8674d93b38549fe < a78e55776522373c446f18d5002a8de4b09e6bf7`
- `Linux >= 94f39804d891cffe4ce17737d295f3b195bc7299 < cd8ae32e4e4652db55bce6b9c79267d8946765a9`
- `Linux fb58962aa3b9359988c7b5b15a971fd9ad5b0ecd`
- `Linux c67d4e7a8f90fb6361ca89d4d5c9a28f4e935e47`
- `Linux >= 6.1.191 < 6.2`
- `Linux >= 6.15.11 < 6.16`
- `Linux >= 6.6.103 < 6.6.109`
- `Linux >= 6.12.43 < 6.12.50`
- `Linux >= 6.16.2 < 6.16.10`

## Remediation

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