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Fencer Vulns
critical 9.8

CVE-2026-74586 in the critical feed json

sctp: clear new_transport when removing a peer

published 2026-08-22 2 mo ago modified 2026-10-16 23 d ago also EUVD-2026-64523

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: 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.

Patch / fix

  • Linux Linux 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.105-1
  • linux Debian 14 7.1.9-1
  • linux-6.12 Debian 12 6.12.107-1~deb12u1

debian advisories DEBIAN-CVE-2026-74586

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1113.119
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1111.115

ubuntu advisories UBUNTU-CVE-2026-74586

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-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-2026:22091-1

  • 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-2026:95100ALSA-2026:95212ALSA-2026:95367

  • kernel Rocky Linux 10 6.12.0-211.74.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.66.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.184.1.rt7.525.el8_10
  • kernel Rocky Linux 8 4.18.0-553.184.1.el8_10

rocky linux advisories RLSA-2026:95367RLSA-2026:95370RLSA-2026:95100RLSA-2026:95212

  • kernel Azure Linux 3.0 6.6.152.1-1

azure linux advisories AZL-97374

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-2026-74586 updated cvss 7.5

kernel: sctp: clear new_transport when removing a peer

  • 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
    affected: workaround, no fix available
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • 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 AppStream (v. 10) rv 6.12.0-211.74.1.el10_2, perf 6.12.0-211.74.1.el10_2, rtla 6.12.0-211.74.1.el10_2, python3-perf 6.12.0-211.74.1.el10_2, kernel-devel-matched 6.12.0-211.74.1.el10_2, kernel-64k-devel-matched 6.12.0-211.74.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.184.1.el8_10, kernel 4.18.0-553.184.1.el8_10, bpftool 4.18.0-553.184.1.el8_10, kernel-core 4.18.0-553.184.1.el8_10, kernel-tools 4.18.0-553.184.1.el8_10, python3-perf 4.18.0-553.184.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:95212
  • 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
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.74.1.el10_2, kernel-64k 6.12.0-211.74.1.el10_2, kernel-core 6.12.0-211.74.1.el10_2, kernel-tools 6.12.0-211.74.1.el10_2, kernel-modules 6.12.0-211.74.1.el10_2, kernel-64k-core 6.12.0-211.74.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:95367
  • 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
show 10 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.184.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.184.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.184.1.el8_10
    fixed: vendor fix RHSA-2026:95212
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-kvm 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-core 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-modules 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-kvm 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-core 4.18.0-553.184.1.rt7.525.el8_10, +4 more
    fixed: vendor fix RHSA-2026:95100
  • 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
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.74.1.el10_2, kernel-rt-64k 6.12.0-211.74.1.el10_2, kernel-rt-core 6.12.0-211.74.1.el10_2, kernel-rt-modules 6.12.0-211.74.1.el10_2, kernel-rt-64k-core 6.12.0-211.74.1.el10_2, kernel-rt-debug-core 6.12.0-211.74.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:95367
  • 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
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.74.1.el10_2, kernel-rt-core 6.12.0-211.74.1.el10_2, kernel-rt-modules 6.12.0-211.74.1.el10_2, kernel-rt-debug-core 6.12.0-211.74.1.el10_2, kernel-rt-modules-core 6.12.0-211.74.1.el10_2, kernel-rt-debug-modules 6.12.0-211.74.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-core 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-modules 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-core 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-debug-modules 4.18.0-553.184.1.rt7.525.el8_10, kernel-rt-modules-extra 4.18.0-553.184.1.rt7.525.el8_10, +2 more
    fixed: vendor fix RHSA-2026:95100
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    not affected: vulnerable code not present

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.