---
id: CVE-2026-74587
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sctp: fix use-after-free of cached ASCONF chunk

  addip_last_asconf caches the outstanding outbound ASCONF chunk
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sctp: fix use-after-free of cached ASCONF chunk

  addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal
  ASCONF-ACK completion path releases the chun…
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 >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    10459b03e2d9ee12435e96f587de4d4cacdbf435
  - >-
    Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    e1bb114e09372fd6e03387ced9ef566da336ed6c
  - >-
    Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    179676f0166230c80053a392303485b37c93dd33
  - >-
    Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d
  - >-
    Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    618b5c6d049896fcfabb91afc072954c92cb2693
  - >-
    Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    07daf4f9750104960a1d60831b2353c0d41f35fb
  - >-
    Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    d949992bc3f00027a2c755e860a11950c75f6073
  - >-
    Linux >= a000c01e60e40e15304ffe48fff051d17a7bea91 <
    8c283e7b56adce00193837f3311b06662466fb21
  - Linux 3.0
published: '2026-08-22'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:17:41.753'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74587'
references:
  - url: 'https://git.kernel.org/stable/c/07daf4f9750104960a1d60831b2353c0d41f35fb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/10459b03e2d9ee12435e96f587de4d4cacdbf435'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/179676f0166230c80053a392303485b37c93dd33'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/618b5c6d049896fcfabb91afc072954c92cb2693'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8c283e7b56adce00193837f3311b06662466fb21'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d949992bc3f00027a2c755e860a11950c75f6073'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dc67d528c2fa939cec7fe3bf7f3089c8d281ca3d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e1bb114e09372fd6e03387ced9ef566da336ed6c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.005
epssPercentile: 0.42613
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T19:01:25.161847Z'
ingestedAt: '2026-08-23T06:43:33.596Z'
---

## Overview

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

sctp: fix use-after-free of cached ASCONF chunk

addip_last_asconf caches the outstanding outbound ASCONF chunk. The normal
ASCONF-ACK completion path releases the chunk and clears the pointer.

However, sctp_asconf_queue_teardown() releases the cached chunk without
clearing addip_last_asconf. During peer restart handling,
sctp_sf_do_dupcook_a() queues SCTP_CMD_PURGE_ASCONF_QUEUE, which invokes
sctp_asconf_queue_teardown() while the association remains alive and leaves
the pointer dangling.

A delayed authenticated ASCONF-ACK can then reach sctp_sf_do_asconf_ack(),
which accesses the stale chunk and passes it to sctp_process_asconf_ack(),
causing a use-after-free and a second release.

Clearing the pointer exposes a race with T4 expiry. Peer restart handling
queues the timer stop before the purge, but SCTP_CMD_TIMER_STOP uses
timer_delete(), which does not wait for a callback already running on
another CPU. Such a callback can reach sctp_sf_t4_timer_expire() after
the purge and dereference NULL.

Clear addip_last_asconf after releasing the cached chunk, and make
sctp_sf_t4_timer_expire() consume a stale T4 expiry if no outstanding
ASCONF remains.

## Remediation

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