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Fencer Vulns
critical 9.8

CVE-2026-89479 in the critical feed json

sctp: stop processing a packet once its association is deleted

published 2026-09-11 58 d ago modified 2026-10-19 21 d ago also EUVD-2026-76385

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

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

sctp: stop processing a packet once its association is deleted

sctp_endpoint_bh_rcv() looks the association up only when chunk->asoc is NULL, and caches the result in chunk->asoc and chunk->transport without taking a reference.

A packet that matches no association is handed to the endpoint, so a peer can bundle COOKIE ECHO, SHUTDOWN and SHUTDOWN ACK in one packet. The COOKIE ECHO creates the association, the SHUTDOWN chunk caches it, and with the outqueue empty the SHUTDOWN ACK reaches sctp_sf_do_9_2_final(), so the association and its transports are freed.

The endpoint loop has no counterpart to the asoc->base.dead check in sctp_assoc_bh_rcv(). The next chunk writes to last_time_heard in the freed transport and is then passed to sctp_do_sm() with the freed association. The transport is freed through RCU, so this needs the packet to come off the socket backlog, where the loop runs in task context.

The endpoint loop cannot do the same check: it holds no reference on the association, so reading asoc->base.dead would itself be a use-after-free. Mark the packet for discard in the command interpreter, just before it deletes the association. That is also before sctp_inq_free() releases the chunk on the association receive path.

sctp_sf_do_5_2_4_dupcook() issues SCTP_CMD_DELETE_TCB for the temporary association, while the one the packet belongs to stays alive. A restarting peer can bundle DATA behind its COOKIE ECHO, so compare against chunk->asoc and leave that case alone.

Patch / fix

  • Linux Linux 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-89479

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-89479

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 8 4.18.0-553.176.1.el8_10
  • perf RHEL 8 4.18.0-553.176.1.el8_10
  • bpftool RHEL 8 4.18.0-553.176.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.176.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.176.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.176.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.176.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.176.1.el8_10

red hat advisories RHSA-2026:85773RHSA-2026:85774

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.84.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.84.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1.150700.17.47.1

suse advisories SUSE-SU-2026:4706-1SUSE-SU-2026:4687-1SUSE-SU-2026:4668-1SUSE-SU-2026:4667-1SUSE-SU-2026:4666-1SUSE-SU-2026:4665-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.39.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.39.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.39.1

opensuse advisories openSUSE-SU-2026:22091-1openSUSE-SU-2026:11880-1

  • kernel AlmaLinux 9 5.14.0-687.66.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.66.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.66.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.66.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.66.1.el9_8

almalinux advisories ALSA-2026:95370ALSA-2026:85773ALSA-2026:85774

  • kernel Rocky Linux 9 5.14.0-687.66.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.176.1.rt7.517.el8_10
  • kernel Rocky Linux 8 4.18.0-553.176.1.el8_10

rocky linux advisories RLSA-2026:95370RLSA-2026:85774RLSA-2026:85773

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-100410

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-89479 updated cvss 8.8

kernel: sctp: stop processing a packet once its association is deleted

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    under investigation
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.66.1.el9_8, perf 5.14.0-687.66.1.el9_8, rtla 5.14.0-687.66.1.el9_8, python3-perf 5.14.0-687.66.1.el9_8, kernel-devel-matched 5.14.0-687.66.1.el9_8, kernel-64k-devel-matched 5.14.0-687.66.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.176.1.el8_10, kernel 4.18.0-553.176.1.el8_10, bpftool 4.18.0-553.176.1.el8_10, kernel-core 4.18.0-553.176.1.el8_10, kernel-tools 4.18.0-553.176.1.el8_10, python3-perf 4.18.0-553.176.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:85773
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.66.1.el9_8, kernel-64k 5.14.0-687.66.1.el9_8, kernel-core 5.14.0-687.66.1.el9_8, kernel-tools 5.14.0-687.66.1.el9_8, kernel-modules 5.14.0-687.66.1.el9_8, kernel-64k-core 5.14.0-687.66.1.el9_8, +27 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.66.1.el9_8
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.176.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.176.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.176.1.el8_10
    fixed: vendor fix RHSA-2026:85773
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-kvm 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-core 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-modules 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-debug-kvm 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-debug-core 4.18.0-553.176.1.rt7.517.el8_10, +4 more
    fixed: vendor fix RHSA-2026:85774
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.66.1.el9_8, kernel-rt-64k 5.14.0-687.66.1.el9_8, kernel-rt-core 5.14.0-687.66.1.el9_8, kernel-rt-modules 5.14.0-687.66.1.el9_8, kernel-rt-64k-core 5.14.0-687.66.1.el9_8, kernel-rt-debug-core 5.14.0-687.66.1.el9_8, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.66.1.el9_8, kernel-rt-core 5.14.0-687.66.1.el9_8, kernel-rt-modules 5.14.0-687.66.1.el9_8, kernel-rt-debug-core 5.14.0-687.66.1.el9_8, kernel-rt-modules-core 5.14.0-687.66.1.el9_8, kernel-rt-debug-modules 5.14.0-687.66.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:95370
show 1 more
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-core 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-modules 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-debug-core 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-debug-modules 4.18.0-553.176.1.rt7.517.el8_10, kernel-rt-modules-extra 4.18.0-553.176.1.rt7.517.el8_10, +2 more
    fixed: vendor fix RHSA-2026:85774

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.