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Fencer Vulns
high 8.0

CVE-2026-53256 json

Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()

published 2026-06-25 4 mo ago modified 2026-10-19 20 d ago also EUVD-2026-39207

cvss
8.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

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

Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()

rfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock, but returns the selected listener after dropping that lock without taking a reference. rfcomm_connect_ind() then locks the listener, queues a child socket on it, and may notify it after unlocking it.

The buggy scenario involves two paths, with each column showing the order within that path:

rfcomm_connect_ind(): listener close: 1. Find parent in 1. close() enters rfcomm_get_sock_by_channel() rfcomm_sock_release(). 2. Drop rfcomm_sk_list.lock 2. rfcomm_sock_shutdown() without pinning parent. closes the listener. 3. Call lock_sock(parent) and 3. rfcomm_sock_kill() bt_accept_enqueue(parent, unlinks and puts parent. sk, true). 4. Read parent flags and may 4. parent can be freed. call sk_state_change().

If close wins the race, parent can be freed before rfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the deferred-setup callback.

Take a reference on the listener before leaving rfcomm_sk_list.lock. After lock_sock() succeeds, recheck that it is still in BT_LISTEN before queueing a child, cache the deferred-setup bit while the parent is locked, and drop the reference after the last parent use.

KASAN reported a slab-use-after-free in lock_sock_nested() from rfcomm_connect_ind(), with the freeing stack going through rfcomm_sock_kill() and rfcomm_sock_release().

Patch / fix

  • Linux Linux 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13, 7.1
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.94-1
  • linux Debian 14 7.0.13-1

debian advisories DEBIAN-CVE-2026-53256

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 24.04 LTS 6.8.0-146.146
  • linux Ubuntu 26.04 LTS 7.0.0-31.31
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1066.69
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1012.12
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1070.78

ubuntu advisories UBUNTU-CVE-2026-53256

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-rt RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-kvm RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-core RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-modules RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-debug-kvm RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-debug-core RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-debug-modules RHEL 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel-rt-modules-extra RHEL 8 4.18.0-553.166.1.rt7.507.el8_10

red hat advisories RHSA-2026:70403RHSA-2026:70402RHSA-2026:67150RHSA-2026:65334

  • kernel-64kb SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS, SLE High Performance Computing 15 SP5-ESPOS 5.14.21-150500.55.182.1
  • kernel-syms SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.182.1
  • kernel-source SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.182.1
  • kernel-default SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +3 more 5.14.21-150500.55.182.1
  • kernel-obs-build SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.182.1
  • kernel-default-base SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.182.1.150500.6.85.2
  • kernel-rt SLE Micro 5.5 5.14.21-150500.13.156.1
  • kernel-source-rt SLE Micro 5.5 5.14.21-150500.13.156.1

suse advisories SUSE-SU-2026:3595-1SUSE-SU-2026:3809-1SUSE-SU-2026:3617-1SUSE-SU-2026:3616-1SUSE-SU-2026:3594-1SUSE-SU-2026:3593-1

  • 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 8 4.18.0-553.166.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.166.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.166.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.166.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.166.1.el8_10

almalinux advisories ALSA-2026:70402ALSA-2026:70403ALSA-2026:67150ALSA-2026:65334

  • kernel-rt Rocky Linux 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel Rocky Linux 8 4.18.0-553.166.1.el8_10
  • kernel Rocky Linux 9 5.14.0-687.47.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.53.1.el10_2

rocky linux advisories RLSA-2026:70403RLSA-2026:70402RLSA-2026:67150RLSA-2026:65334

  • kernel Azure Linux 3.0 6.6.143.1-1

azure linux advisories AZL-90851

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-2026-53256 updated cvss 7.5

kernel: Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • 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 AppStream (v. 9) rv 5.14.0-687.47.1.el9_8, perf 5.14.0-687.47.1.el9_8, rtla 5.14.0-687.47.1.el9_8, python3-perf 5.14.0-687.47.1.el9_8, kernel-devel-matched 5.14.0-687.47.1.el9_8, kernel-64k-devel-matched 5.14.0-687.47.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:67150
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.53.1.el10_2, perf 6.12.0-211.53.1.el10_2, rtla 6.12.0-211.53.1.el10_2, python3-perf 6.12.0-211.53.1.el10_2, kernel-devel-matched 6.12.0-211.53.1.el10_2, kernel-64k-devel-matched 6.12.0-211.53.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.166.1.el8_10, kernel 4.18.0-553.166.1.el8_10, bpftool 4.18.0-553.166.1.el8_10, kernel-core 4.18.0-553.166.1.el8_10, kernel-tools 4.18.0-553.166.1.el8_10, python3-perf 4.18.0-553.166.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.47.1.el9_8, kernel-64k 5.14.0-687.47.1.el9_8, kernel-core 5.14.0-687.47.1.el9_8, kernel-tools 5.14.0-687.47.1.el9_8, kernel-modules 5.14.0-687.47.1.el9_8, kernel-64k-core 5.14.0-687.47.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:67150
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.53.1.el10_2, kernel-64k 6.12.0-211.53.1.el10_2, kernel-core 6.12.0-211.53.1.el10_2, kernel-tools 6.12.0-211.53.1.el10_2, kernel-modules 6.12.0-211.53.1.el10_2, kernel-64k-core 6.12.0-211.53.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.47.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.47.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.47.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.47.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.47.1.el9_8
    fixed: vendor fix RHSA-2026:67150
show 8 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.53.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.53.1.el10_2
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.166.1.el8_10
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, +4 more
    fixed: vendor fix RHSA-2026:70403
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.47.1.el9_8, kernel-rt-64k 5.14.0-687.47.1.el9_8, kernel-rt-core 5.14.0-687.47.1.el9_8, kernel-rt-modules 5.14.0-687.47.1.el9_8, kernel-rt-64k-core 5.14.0-687.47.1.el9_8, kernel-rt-debug-core 5.14.0-687.47.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:67150
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.53.1.el10_2, kernel-rt-64k 6.12.0-211.53.1.el10_2, kernel-rt-core 6.12.0-211.53.1.el10_2, kernel-rt-modules 6.12.0-211.53.1.el10_2, kernel-rt-64k-core 6.12.0-211.53.1.el10_2, kernel-rt-debug-core 6.12.0-211.53.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.47.1.el9_8, kernel-rt-core 5.14.0-687.47.1.el9_8, kernel-rt-modules 5.14.0-687.47.1.el9_8, kernel-rt-debug-core 5.14.0-687.47.1.el9_8, kernel-rt-modules-core 5.14.0-687.47.1.el9_8, kernel-rt-debug-modules 5.14.0-687.47.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:67150
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.53.1.el10_2, kernel-rt-core 6.12.0-211.53.1.el10_2, kernel-rt-modules 6.12.0-211.53.1.el10_2, kernel-rt-debug-core 6.12.0-211.53.1.el10_2, kernel-rt-modules-core 6.12.0-211.53.1.el10_2, kernel-rt-debug-modules 6.12.0-211.53.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:65334
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules-extra 4.18.0-553.166.1.rt7.507.el8_10, +2 more
    fixed: vendor fix RHSA-2026:70403

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 ICSA-26-295-16 updated cvss 8.0

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.0 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness
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.