---
id: CVE-2026-74586
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sctp: clear new_transport when removing a peer

  sctp_process_asconf_param() stores a newly added peer transport in
  asoc->new_transport
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sctp: clear new_transport when removing a peer

  sctp_process_asconf_param() stores a newly added peer transport in
  asoc->new_transport. After all parameters in the ASCO…
severity: none
published: '2026-08-22'
updated: '2026-08-22'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74586'
references:
  - url: 'https://git.kernel.org/stable/c/163847552a571bd55094291f4ffcdc1de0f14a7b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/291accf36febce751021888de5f15090f4875b56'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/31efa656cf6aface26e88f038c14f22ee6ca1500'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3b539b317cd052236fed0350364ff1268996ba46'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/beb33f8ee1ca83acddb2a5ae80f3d22ec550b4c3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c0f973bb5118dd1b146cda3fcc8af6f6057befec'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ca33df36aa0143a1d04f57d2086020c12e7eddb7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/db9d8e3b670f841755bc2018f178472dc6064d27'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - exploit-available
ingestedAt: '2026-08-23T06:43:33.556Z'
epss: 0.00734
epssPercentile: 0.52369
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/TarPeg007/CVE-2026-74586'
  checkedAt: '2026-09-25T08:21:12.198Z'
exploitAvailable: true
---

## Overview

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

sctp: clear new_transport when removing a peer

sctp_process_asconf_param() stores a newly added peer transport in
asoc->new_transport. After all parameters in the ASCONF chunk have been
processed, sctp_sf_do_asconf() uses this pointer to send a HEARTBEAT to the
new transport.

An authenticated ASCONF from a remote SCTP peer can add a transport and
remove it again with a wildcard DEL-IP parameter in the same chunk. The
wildcard deletion preserves the transport on which the ASCONF arrived, but
removes the newly added transport through
sctp_assoc_del_nonprimary_peers(). The removal does not clear
asoc->new_transport, leaving it pointing to the removed transport.

sctp_sf_do_asconf() then creates a HEARTBEAT whose chunk->transport points
to the removed transport without holding a transport reference. During
local address replacement, src_out_of_asoc_ok keeps this HEARTBEAT on
control_chunk_list. After the transport is freed by RCU, a successful
ASCONF_ACK for the replacement address releases the queued HEARTBEAT and
sctp_outq_select_transport() reads the freed transport's state.

The issue was found during a static audit of SCTP objects. With an
authenticated peer, the reproducer triggered the same KASAN report in 2
of 2 unpatched runs on a KASAN-enabled netdev/main kernel:

  BUG: KASAN: slab-use-after-free in sctp_outq_select_transport
  Read of size 4 at addr ffff88800b9bd95c by task python3/197

  Call Trace:
   sctp_outq_select_transport+0x549/0x8b0 [sctp]
   sctp_outq_flush+0x306/0x2c60 [sctp]
   sctp_transport_immediate_rtx+0xaf/0x260 [sctp]
   sctp_process_asconf_ack+0xa48/0xf70 [sctp]

  Allocated by task 197:
   sctp_transport_new+0x68/0x650 [sctp]
   sctp_assoc_add_peer+0x258/0x12a0 [sctp]
   sctp_process_asconf+0x5e9/0x1090 [sctp]

  Last potentially related work creation:
   __call_rcu_common.constprop.0+0x77/0xb70
   sctp_assoc_del_nonprimary_peers+0x7c/0xd0 [sctp]
   sctp_process_asconf+0xd9c/0x1090 [sctp]

The first invalid access was a four-byte read of transport->state at
net/sctp/outqueue.c:833. The same reproducer completed the full
authenticated ASCONF and local-address replacement sequence with this
change without a KASAN report or oops.

Clear new_transport when its peer is removed, before it can be used to
create the HEARTBEAT.

## Remediation

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