---
id: CVE-2026-89478
title: 'sctp: drop a chunk if its transport was removed'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sctp: drop a chunk if its transport was removed

  sctp_rcv() resolves the transport once per packet and leaves it in
  chunk->transport. The lookup reference, or the one s…
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'
cvssSource: cna
cwe:
  - CWE-825
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    3fc072e7cb4a0ff251d13cfc2d24f62489cd9386
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    d7cb5ad832095dc4becfdb2a36007ffd50e49fb0
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    0422b092a3d43ca462932ff9f747731ca078d1d4
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    928fd7920ba37cc5637a211b9be979083413a2fa
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    c6c86a5e62a4fec36692ddd64b9144b660f71f96
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    1035bdef1efb9b1076d1a57b81e08c637ff08ecc
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    3537961df2163258bddc230db0e18dc14e925ea6
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    03a9d10ecf71f54b2af8020935f2033d4a132be5
  - Linux 2.6.12
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T19:22:25.085426Z'
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:47:27.202Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89478'
references:
  - url: 'https://git.kernel.org/stable/c/3fc072e7cb4a0ff251d13cfc2d24f62489cd9386'
  - url: 'https://git.kernel.org/stable/c/d7cb5ad832095dc4becfdb2a36007ffd50e49fb0'
  - url: 'https://git.kernel.org/stable/c/0422b092a3d43ca462932ff9f747731ca078d1d4'
  - url: 'https://git.kernel.org/stable/c/928fd7920ba37cc5637a211b9be979083413a2fa'
  - url: 'https://git.kernel.org/stable/c/c6c86a5e62a4fec36692ddd64b9144b660f71f96'
  - url: 'https://git.kernel.org/stable/c/1035bdef1efb9b1076d1a57b81e08c637ff08ecc'
  - url: 'https://git.kernel.org/stable/c/3537961df2163258bddc230db0e18dc14e925ea6'
  - url: 'https://git.kernel.org/stable/c/03a9d10ecf71f54b2af8020935f2033d4a132be5'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89478.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89478'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532439'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89478'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89478'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89478.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00514
epssPercentile: 0.43609
scores:
  cna: 9.8
  vendor: 7
ingestedAt: '2026-09-14T15:23:07.453Z'
---

## Overview

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

sctp: drop a chunk if its transport was removed

sctp_rcv() resolves the transport once per packet and leaves it in
chunk->transport. The lookup reference, or the one sctp_add_backlog() takes
if the socket is owned by userspace, keeps it around until the chunk has
been processed.

An authenticated ASCONF DEL-IP can remove it in the meantime.
sctp_assoc_rm_peer() takes the transport out of the association and calls
sctp_transport_free(), which tags it dead and drops the reference the
association held. There is a window on both paths: the packet can sit on
the socket backlog, and on the direct path the lookup completes before
bh_lock_sock().

The DATA chunk in that packet puts the removed transport back into
asoc->peer.last_data_from. Once the packet is done that reference goes
away and the transport is freed by RCU, so the next delayed SACK carries
the pointer into the SACK chunk and sctp_outq_select_transport() reads the
freed transport's state.

Drop the chunk in sctp_inq_push(), next to the existing rcvr->dead check.
Both paths reach it with the association's socket lock held. The peer
retransmits it.

## Affected

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3fc072e7cb4a0ff251d13cfc2d24f62489cd9386`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d7cb5ad832095dc4becfdb2a36007ffd50e49fb0`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0422b092a3d43ca462932ff9f747731ca078d1d4`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 928fd7920ba37cc5637a211b9be979083413a2fa`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c6c86a5e62a4fec36692ddd64b9144b660f71f96`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1035bdef1efb9b1076d1a57b81e08c637ff08ecc`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3537961df2163258bddc230db0e18dc14e925ea6`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 03a9d10ecf71f54b2af8020935f2033d4a132be5`
- `Linux 2.6.12`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89478.json)