---
id: CVE-2026-74581
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: ipv6: clear suppressed fib6 rule result

  fib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(),
  but leaves res->rt6 pointing at the released rt6_in…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: ipv6: clear suppressed fib6 rule result

  fib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(),
  but leaves res->rt6 pointing at the released rt6_in…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 209d35ee34e25f9668c404350a1c86d914c54ffa <
    90c57310e266eb94e4a80d6b15a9ca131d2e82cb
  - >-
    Linux >= 8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383 <
    5d29b286c9de0b309e94b9ed083aa1a2f429434f
  - >-
    Linux >= cdef485217d30382f3bf6448c54b4401648fe3f1 <
    354db6243eca59e9d187ffbf8b7955b044ce84dc
  - >-
    Linux >= cdef485217d30382f3bf6448c54b4401648fe3f1 <
    6d98c70fe0ba8c7708bfd5b2a5174d2086775daa
  - >-
    Linux >= cdef485217d30382f3bf6448c54b4401648fe3f1 <
    9bad152c42b37499162367fe47867411e62fffa3
  - >-
    Linux >= cdef485217d30382f3bf6448c54b4401648fe3f1 <
    dc3ab04220667f254f4348572b2a0b3febff89fb
  - >-
    Linux >= cdef485217d30382f3bf6448c54b4401648fe3f1 <
    a341c091ca0bfae377747b1b59a3bd8ebe18a937
  - >-
    Linux >= cdef485217d30382f3bf6448c54b4401648fe3f1 <
    6aea62e433fe1b586202a5fee8b5807ce635e1d7
  - Linux ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29
  - Linux >= 5.10.84 < 5.10.265
  - Linux >= 5.15.7 < 5.15.216
  - Linux >= 5.4.164 < 5.5
  - Linux 5.16
published: '2026-08-21'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:17:39.940'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74581'
references:
  - url: 'https://git.kernel.org/stable/c/354db6243eca59e9d187ffbf8b7955b044ce84dc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5d29b286c9de0b309e94b9ed083aa1a2f429434f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6aea62e433fe1b586202a5fee8b5807ce635e1d7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6d98c70fe0ba8c7708bfd5b2a5174d2086775daa'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/90c57310e266eb94e4a80d6b15a9ca131d2e82cb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9bad152c42b37499162367fe47867411e62fffa3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a341c091ca0bfae377747b1b59a3bd8ebe18a937'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dc3ab04220667f254f4348572b2a0b3febff89fb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00421
epssPercentile: 0.36249
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T19:01:10.675016Z'
ingestedAt: '2026-10-14T19:49:57.560Z'
---

## Overview

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

net: ipv6: clear suppressed fib6 rule result

fib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(),
but leaves res->rt6 pointing at the released rt6_info.

If no later rule supplies a replacement, fib6_rule_lookup() still sees
res.rt6 and returns that stale dst to its caller. A suppressing rule can
therefore leak a released route back to rt6_lookup(), and the next put
hits rcuref_put_slowpath() from dst_release().

Clear res->rt6 when suppressing the route so suppressed lookups fall
through to the null dst instead of reusing the released one.

## Remediation

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