---
id: CVE-2025-71304
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smack: /smack/doi: accept previously used values

  Writing to /smack/doi a value that has ever been
  written there in the past disables networking for
  non-ambient labels.…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  smack: /smack/doi: accept previously used values

  Writing to /smack/doi a value that has ever been
  written there in the past disables networking for
  non-ambient labels.…
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'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 2.6.25, < 5.10.252'
  - 'linux_kernel >= 5.11, < 5.15.202'
  - 'linux_kernel >= 5.16, < 6.1.165'
  - 'linux_kernel >= 6.2, < 6.6.128'
  - 'linux_kernel >= 6.7, < 6.12.75'
  - 'linux_kernel >= 6.13, < 6.18.14'
  - 'linux_kernel >= 6.19, < 6.19.4'
patched:
  - linux_kernel 6.19.4
published: '2026-05-27'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-71304'
references:
  - url: 'https://git.kernel.org/stable/c/199452f22d2f74b897fe826f81ec402b0a8461a0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1c7ee23dfcd18d80770d8f90f2ab5bb1b2bfd8a3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/33d589ed60ae433b483761987b85e0d24e54584e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5a247a84de0ba44edbbd6be851c8a6b2aa60ff85'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6ec091c5c7eeabd249a7c46813cad1e9f555f859'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8beebb8ad9a003f978e53b06237986588223e15e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/eb718a3c8181ada679340db34cd61bce48e44749'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f8071500177f38cff38892bd85ac631cc6e010b2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.0016
epssPercentile: 0.04732
ingestedAt: '2026-10-14T13:30:58.504Z'
---

## Overview

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

smack: /smack/doi: accept previously used values

Writing to /smack/doi a value that has ever been
written there in the past disables networking for
non-ambient labels.
E.g.

    # cat /smack/doi
    3
    # netlabelctl -p cipso list
    Configured CIPSO mappings (1)
     DOI value : 3
       mapping type : PASS_THROUGH
    # netlabelctl -p map list
    Configured NetLabel domain mappings (3)
     domain: "_" (IPv4)
       protocol: UNLABELED
     domain: DEFAULT (IPv4)
       protocol: CIPSO, DOI = 3
     domain: DEFAULT (IPv6)
       protocol: UNLABELED

    # cat /smack/ambient
    _
    # cat /proc/$$/attr/smack/current
    _
    # ping -c1 10.1.95.12
    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.964 ms
    # echo foo >/proc/$$/attr/smack/current
    # ping -c1 10.1.95.12
    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.956 ms
    unknown option 86

    # echo 4 >/smack/doi
    # echo 3 >/smack/doi
!>  [  214.050395] smk_cipso_doi:691 cipso add rc = -17
    # echo 3 >/smack/doi
!>  [  249.402261] smk_cipso_doi:678 remove rc = -2
!>  [  249.402261] smk_cipso_doi:691 cipso add rc = -17

    # ping -c1 10.1.95.12
!!> ping: 10.1.95.12: Address family for hostname not supported

    # echo _ >/proc/$$/attr/smack/current
    # ping -c1 10.1.95.12
    64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.617 ms

This happens because Smack keeps decommissioned DOIs,
fails to re-add them, and consequently refuses to add
the “default” domain map:

    # netlabelctl -p cipso list
    Configured CIPSO mappings (2)
     DOI value : 3
       mapping type : PASS_THROUGH
     DOI value : 4
       mapping type : PASS_THROUGH
    # netlabelctl -p map list
    Configured NetLabel domain mappings (2)
     domain: "_" (IPv4)
       protocol: UNLABELED
!>  (no ipv4 map for default domain here)
     domain: DEFAULT (IPv6)
       protocol: UNLABELED

Fix by clearing decommissioned DOI definitions and
serializing concurrent DOI updates with a new lock.

Also:
- allow /smack/doi to live unconfigured, since
  adding a map (netlbl_cfg_cipsov4_map_add) may fail.
  CIPSO_V4_DOI_UNKNOWN(0) indicates the unconfigured DOI
- add new DOI before removing the old default map,
  so the old map remains if the add fails

(2008-02-04, Casey Schaufler)

## Affected

- `linux_kernel >= 2.6.25, < 5.10.252`
- `linux_kernel >= 5.11, < 5.15.202`
- `linux_kernel >= 5.16, < 6.1.165`
- `linux_kernel >= 6.2, < 6.6.128`
- `linux_kernel >= 6.7, < 6.12.75`
- `linux_kernel >= 6.13, < 6.18.14`
- `linux_kernel >= 6.19, < 6.19.4`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.4`