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Fencer Intel
high 7.8

CVE-2026-43023 json

Bluetooth: SCO: fix race conditions in sco_sock_connect()

published 6mo ago modified 21d ago also EUVD-2026-26622

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 0%
public exploits
0
none known

Summary

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

Bluetooth: SCO: fix race conditions in sco_sock_connect()

sco_sock_connect() checks sk_state and sk_type without holding the socket lock. Two concurrent connect() syscalls on the same socket can both pass the check and enter sco_connect(), leading to use-after-free.

The buggy scenario involves three participants and was confirmed with additional logging instrumentation:

Thread A (connect): HCI disconnect: Thread B (connect):

sco_sock_connect(sk) sco_sock_connect(sk) sk_state==BT_OPEN sk_state==BT_OPEN (pass, no lock) (pass, no lock) sco_connect(sk): sco_connect(sk): hci_dev_lock hci_dev_lock hci_connect_sco <- blocked -> hcon1 sco_conn_add->conn1 lock_sock(sk) sco_chan_add: conn1->sk = sk sk->conn = conn1 sk_state=BT_CONNECT release_sock hci_dev_unlock hci_dev_lock sco_conn_del: lock_sock(sk) sco_chan_del: sk->conn=NULL conn1->sk=NULL sk_state= BT_CLOSED SOCK_ZAPPED release_sock hci_dev_unlock (unblocked) hci_connect_sco -> hcon2 sco_conn_add -> conn2 lock_sock(sk) sco_chan_add: sk->conn=conn2 sk_state= BT_CONNECT // zombie sk! release_sock hci_dev_unlock

Thread B revives a BT_CLOSED + SOCK_ZAPPED socket back to BT_CONNECT. Subsequent cleanup triggers double sock_put() and use-after-free. Meanwhile conn1 is leaked as it was orphaned when sco_conn_del() cleared the association.

Fix this by: - Moving lock_sock() before the sk_state/sk_type checks in sco_sock_connect() to serialize concurrent connect attempts - Fixing the sk_type != SOCK_SEQPACKET check to actually return the error instead of just assigning it - Adding a state re-check in sco_connect() after lock_sock() to catch state changes during the window between the locks - Adding sco_pi(sk)->conn check in sco_chan_add() to prevent double-attach of a socket to multiple connections - Adding hci_conn_drop() on sco_chan_add failure to prevent HCI connection leaks

Patch / fix

  • Linux Linux 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12, 7.0
  • linux Debian 12 6.1.170-1
  • linux Debian 13 6.12.85-1
  • linux Debian 14 6.19.12-1

debian advisories DEBIAN-CVE-2026-43023

  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1059.67
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1061.62
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1063.71
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1046.50
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1061.65

ubuntu advisories UBUNTU-CVE-2026-43023

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 9 5.14.0-687.12.1.el9_8
  • rv RHEL 9 5.14.0-687.12.1.el9_8
  • perf RHEL 9 5.14.0-687.12.1.el9_8
  • rtla RHEL 9 5.14.0-687.12.1.el9_8
  • libperf RHEL 9 5.14.0-687.12.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.12.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.12.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.12.1.el9_8

red hat advisories RHSA-2026:62568RHSA-2026:61351RHSA-2026:21556RHSA-2026:21557

  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.37.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.37.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1.160000.2.19
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-azure SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1
  • kernel-obs-qa SLES 16.0, SLES for SAP applications 16.0 6.12.0-160000.37.1

suse advisories SUSE-SU-2026:23237-1SUSE-SU-2026:23068-1SUSE-SU-2026:23221-1SUSE-SU-2026:23231-1SUSE-SU-2026:23066-1SUSE-SU-2026:2799-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.37.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.37.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.37.1

opensuse advisories openSUSE-SU-2026:21555-1

  • kernel AlmaLinux 9 5.14.0-687.12.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.12.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.12.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.12.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.12.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.12.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.12.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.12.1.el9_8

almalinux advisories ALSA-2026:21556ALSA-2026:21557

  • kernel Rocky Linux 10 6.12.0-211.18.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.12.1.el9_8

rocky linux advisories RLSA-2026:21557RLSA-2026:21556

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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-2026-43023 updated cvss 7.0

kernel: Bluetooth: SCO: fix race conditions in sco_sock_connect()

  • Red Hat CodeReady Linux Builder EUS (v.9.6) libperf 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.138.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.138.1.el9_6
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.12.1.el9_8, perf 5.14.0-687.12.1.el9_8, rtla 5.14.0-687.12.1.el9_8, python3-perf 5.14.0-687.12.1.el9_8, kernel-devel-matched 5.14.0-687.12.1.el9_8, kernel-64k-devel-matched 5.14.0-687.12.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.18.1.el10_2, perf 6.12.0-211.18.1.el10_2, rtla 6.12.0-211.18.1.el10_2, python3-perf 6.12.0-211.18.1.el10_2, kernel-devel-matched 6.12.0-211.18.1.el10_2, kernel-64k-devel-matched 6.12.0-211.18.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:21557
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) rv 5.14.0-427.158.1.el9_4, perf 5.14.0-427.158.1.el9_4, rtla 5.14.0-427.158.1.el9_4, kernel-devel-matched 5.14.0-427.158.1.el9_4, kernel-64k-devel-matched 5.14.0-427.158.1.el9_4, kernel-debug-devel-matched 5.14.0-427.158.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.99.1.el10_0, perf 6.12.0-55.99.1.el10_0, rtla 6.12.0-55.99.1.el10_0, python3-perf 6.12.0-55.99.1.el10_0, kernel-devel-matched 6.12.0-55.99.1.el10_0, kernel-64k-devel-matched 6.12.0-55.99.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:61351
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.138.1.el9_6, perf 5.14.0-570.138.1.el9_6, rtla 5.14.0-570.138.1.el9_6, python3-perf 5.14.0-570.138.1.el9_6, kernel-devel-matched 5.14.0-570.138.1.el9_6, kernel-64k-devel-matched 5.14.0-570.138.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.12.1.el9_8, kernel-64k 5.14.0-687.12.1.el9_8, kernel-core 5.14.0-687.12.1.el9_8, kernel-tools 5.14.0-687.12.1.el9_8, kernel-modules 5.14.0-687.12.1.el9_8, kernel-64k-core 5.14.0-687.12.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.18.1.el10_2, kernel-64k 6.12.0-211.18.1.el10_2, kernel-core 6.12.0-211.18.1.el10_2, kernel-tools 6.12.0-211.18.1.el10_2, kernel-modules 6.12.0-211.18.1.el10_2, kernel-64k-core 6.12.0-211.18.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:21557
show 17 more
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool 7.3.0-427.158.1.el9_4, kernel 5.14.0-427.158.1.el9_4, kernel-64k 5.14.0-427.158.1.el9_4, kernel-core 5.14.0-427.158.1.el9_4, kernel-tools 5.14.0-427.158.1.el9_4, python3-perf 5.14.0-427.158.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.99.1.el10_0, kernel-64k 6.12.0-55.99.1.el10_0, kernel-core 6.12.0-55.99.1.el10_0, kernel-tools 6.12.0-55.99.1.el10_0, kernel-modules 6.12.0-55.99.1.el10_0, kernel-64k-core 6.12.0-55.99.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:61351
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.138.1.el9_6, kernel-64k 5.14.0-570.138.1.el9_6, kernel-core 5.14.0-570.138.1.el9_6, kernel-tools 5.14.0-570.138.1.el9_6, kernel-modules 5.14.0-570.138.1.el9_6, kernel-64k-core 5.14.0-570.138.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.12.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.12.1.el9_8
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.18.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.18.1.el10_2
    fixed: vendor fix RHSA-2026:21557
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.99.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.99.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.99.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.99.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.99.1.el10_0
    fixed: vendor fix RHSA-2026:61351
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.12.1.el9_8, kernel-rt-64k 5.14.0-687.12.1.el9_8, kernel-rt-core 5.14.0-687.12.1.el9_8, kernel-rt-modules 5.14.0-687.12.1.el9_8, kernel-rt-64k-core 5.14.0-687.12.1.el9_8, kernel-rt-debug-core 5.14.0-687.12.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.18.1.el10_2, kernel-rt-64k 6.12.0-211.18.1.el10_2, kernel-rt-core 6.12.0-211.18.1.el10_2, kernel-rt-modules 6.12.0-211.18.1.el10_2, kernel-rt-64k-core 6.12.0-211.18.1.el10_2, kernel-rt-debug-core 6.12.0-211.18.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:21557
  • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt 5.14.0-427.158.1.el9_4, kernel-rt-core 5.14.0-427.158.1.el9_4, kernel-rt-modules 5.14.0-427.158.1.el9_4, kernel-rt-debug-core 5.14.0-427.158.1.el9_4, kernel-rt-modules-core 5.14.0-427.158.1.el9_4, kernel-rt-debug-modules 5.14.0-427.158.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.99.1.el10_0, kernel-rt-64k 6.12.0-55.99.1.el10_0, kernel-rt-core 6.12.0-55.99.1.el10_0, kernel-rt-modules 6.12.0-55.99.1.el10_0, kernel-rt-64k-core 6.12.0-55.99.1.el10_0, kernel-rt-debug-core 6.12.0-55.99.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:61351
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.138.1.el9_6, kernel-rt-64k 5.14.0-570.138.1.el9_6, kernel-rt-core 5.14.0-570.138.1.el9_6, kernel-rt-modules 5.14.0-570.138.1.el9_6, kernel-rt-64k-core 5.14.0-570.138.1.el9_6, kernel-rt-debug-core 5.14.0-570.138.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.12.1.el9_8, kernel-rt-core 5.14.0-687.12.1.el9_8, kernel-rt-modules 5.14.0-687.12.1.el9_8, kernel-rt-debug-core 5.14.0-687.12.1.el9_8, kernel-rt-modules-core 5.14.0-687.12.1.el9_8, kernel-rt-debug-modules 5.14.0-687.12.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:21556
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.18.1.el10_2, kernel-rt-core 6.12.0-211.18.1.el10_2, kernel-rt-modules 6.12.0-211.18.1.el10_2, kernel-rt-debug-core 6.12.0-211.18.1.el10_2, kernel-rt-modules-core 6.12.0-211.18.1.el10_2, kernel-rt-debug-modules 6.12.0-211.18.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:21557
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt 5.14.0-427.158.1.el9_4, kernel-rt-kvm 5.14.0-427.158.1.el9_4, kernel-rt-core 5.14.0-427.158.1.el9_4, kernel-rt-modules 5.14.0-427.158.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.158.1.el9_4, kernel-rt-debug-core 5.14.0-427.158.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:91489
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.99.1.el10_0, kernel-rt-kvm 6.12.0-55.99.1.el10_0, kernel-rt-core 6.12.0-55.99.1.el10_0, kernel-rt-modules 6.12.0-55.99.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.99.1.el10_0, kernel-rt-debug-core 6.12.0-55.99.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:61351
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.138.1.el9_6, kernel-rt-kvm 5.14.0-570.138.1.el9_6, kernel-rt-core 5.14.0-570.138.1.el9_6, kernel-rt-modules 5.14.0-570.138.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.138.1.el9_6, kernel-rt-debug-core 5.14.0-570.138.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:62568
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 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
    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
no
Technical impact
total
Assessed
24d ago

Exploit prediction

0.10% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
Technology feeds

References

Sources

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