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Fencer Vulns
medium 5.5

CVE-2024-27399 json

Bluetooth: l2cap: fix null-ptr-deref in l2cap_chan_timeout

published 2024-05-13 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-24603

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

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

Bluetooth: l2cap: fix null-ptr-deref in l2cap_chan_timeout

There is a race condition between l2cap_chan_timeout() and l2cap_chan_del(). When we use l2cap_chan_del() to delete the channel, the chan->conn will be set to null. But the conn could be dereferenced again in the mutex_lock() of l2cap_chan_timeout(). As a result the null pointer dereference bug will happen. The KASAN report triggered by POC is shown below:

[ 472.074580] ================================================================== [ 472.075284] BUG: KASAN: null-ptr-deref in mutex_lock+0x68/0xc0 [ 472.075308] Write of size 8 at addr 0000000000000158 by task kworker/0:0/7 [ 472.075308] [ 472.075308] CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted 6.9.0-rc5-00356-g78c0094a146b #36 [ 472.075308] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu4 [ 472.075308] Workqueue: events l2cap_chan_timeout [ 472.075308] Call Trace: [ 472.075308] <TASK> [ 472.075308] dump_stack_lvl+0x137/0x1a0 [ 472.075308] print_report+0x101/0x250 [ 472.075308] ? __virt_addr_valid+0x77/0x160 [ 472.075308] ? mutex_lock+0x68/0xc0 [ 472.075308] kasan_report+0x139/0x170 [ 472.075308] ? mutex_lock+0x68/0xc0 [ 472.075308] kasan_check_range+0x2c3/0x2e0 [ 472.075308] mutex_lock+0x68/0xc0 [ 472.075308] l2cap_chan_timeout+0x181/0x300 [ 472.075308] process_one_work+0x5d2/0xe00 [ 472.075308] worker_thread+0xe1d/0x1660 [ 472.075308] ? pr_cont_work+0x5e0/0x5e0 [ 472.075308] kthread+0x2b7/0x350 [ 472.075308] ? pr_cont_work+0x5e0/0x5e0 [ 472.075308] ? kthread_blkcg+0xd0/0xd0 [ 472.075308] ret_from_fork+0x4d/0x80 [ 472.075308] ? kthread_blkcg+0xd0/0xd0 [ 472.075308] ret_from_fork_asm+0x11/0x20 [ 472.075308] </TASK> [ 472.075308] ================================================================== [ 472.094860] Disabling lock debugging due to kernel taint [ 472.096136] BUG: kernel NULL pointer dereference, address: 0000000000000158 [ 472.096136] #PF: supervisor write access in kernel mode [ 472.096136] #PF: error_code(0x0002) - not-present page [ 472.096136] PGD 0 P4D 0 [ 472.096136] Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI [ 472.096136] CPU: 0 PID: 7 Comm: kworker/0:0 Tainted: G B 6.9.0-rc5-00356-g78c0094a146b #36 [ 472.096136] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu4 [ 472.096136] Workqueue: events l2cap_chan_timeout [ 472.096136] RIP: 0010:mutex_lock+0x88/0xc0 [ 472.096136] Code: be 08 00 00 00 e8 f8 23 1f fd 4c 89 f7 be 08 00 00 00 e8 eb 23 1f fd 42 80 3c 23 00 74 08 48 88 [ 472.096136] RSP: 0018:ffff88800744fc78 EFLAGS: 00000246 [ 472.096136] RAX: 0000000000000000 RBX: 1ffff11000e89f8f RCX: ffffffff8457c865 [ 472.096136] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88800744fc78 [ 472.096136] RBP: 0000000000000158 R08: ffff88800744fc7f R09: 1ffff11000e89f8f [ 472.096136] R10: dffffc0000000000 R11: ffffed1000e89f90 R12: dffffc0000000000 [ 472.096136] R13: 0000000000000158 R14: ffff88800744fc78 R15: ffff888007405a00 [ 472.096136] FS: 0000000000000000(0000) GS:ffff88806d200000(0000) knlGS:0000000000000000 [ 472.096136] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 472.096136] CR2: 0000000000000158 CR3: 000000000da32000 CR4: 00000000000006f0 [ 472.096136] Call Trace: [ 472.096136] <TASK> [ 472.096136] ? __die_body+0x8d/0xe0 [ 472.096136] ? page_fault_oops+0x6b8/0x9a0 [ 472.096136] ? kernelmode_fixup_or_oops+0x20c/0x2a0 [ 472.096136] ? do_user_addr_fault+0x1027/0x1340 [ 472.096136] ? _printk+0x7a/0xa0 [ 472.096136] ? mutex_lock+0x68/0xc0 [ 472.096136] ? add_taint+0x42/0xd0 [ 472.096136] ? exc_page_fault+0x6a/0x1b0 [ 472.096136] ? asm_exc_page_fault+0x26/0x30 [ 472.096136] ? mutex_lock+0x75/0xc0 [ 472.096136] ? mutex_lock+0x88/0xc0 [ 472.096136] ? mutex_lock+0x75/0xc0 [ 472.096136] l2cap_chan_timeo ---truncated---

Patch / fix

  • Linux Linux 4.19.314, 5.4.276, 5.10.217, 5.15.159, 6.1.91, 6.6.31, 6.8.10, 6.9
  • linux Debian 12 6.1.94-1
  • linux Debian 14, Debian 13 6.8.11-1

debian advisories DEBIAN-CVE-2024-27399

  • linux Ubuntu 20.04 LTS 5.4.0-192.212
  • linux Ubuntu 22.04 LTS 5.15.0-118.128
  • linux Ubuntu 24.04 LTS 6.8.0-40.40
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1130.140
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1067.73
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1013.14
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1134.143
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1066.74

ubuntu advisories UBUNTU-CVE-2024-27399

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 5.14.0-503.19.1.el9_5
  • rv RHEL 9 5.14.0-503.19.1.el9_5
  • perf RHEL 9 5.14.0-503.19.1.el9_5
  • rtla RHEL 9 5.14.0-503.19.1.el9_5
  • bpftool RHEL 9 7.4.0-503.19.1.el9_5
  • libperf RHEL 9 5.14.0-503.19.1.el9_5
  • kernel-rt RHEL 9 5.14.0-503.19.1.el9_5
  • kernel-64k RHEL 9 5.14.0-503.19.1.el9_5

red hat advisories RHSA-2024:11486RHSA-2024:10773RHSA-2024:10772RHSA-2024:10771RHSA-2024:10281RHSA-2024:6993

  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-25.1
  • kernel-livepatch-MICRO-6-0-RT_Update_5 Linux Micro 6.1, Linux Micro 6.0 1-1.1
  • kernel-rt Linux Micro 6.0 6.4.0-9.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-9.1
  • kernel-source Linux Micro 6.0 6.4.0-18.1
  • kernel-default Linux Micro 6.0 6.4.0-18.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-18.1

suse advisories SUSE-SU-2025:20166-1SUSE-SU-2025:20249-1SUSE-SU-2025:20028-1SUSE-SU-2025:20008-1SUSE-SU-2024:2973-1SUSE-SU-2024:2561-1

  • kernel AlmaLinux 9 5.14.0-503.19.1.el9_5
  • rv AlmaLinux 9 5.14.0-503.19.1.el9_5
  • perf AlmaLinux 9 5.14.0-503.19.1.el9_5
  • rtla AlmaLinux 9 5.14.0-503.19.1.el9_5
  • bpftool AlmaLinux 9 7.4.0-503.19.1.el9_5
  • libperf AlmaLinux 9 5.14.0-503.19.1.el9_5
  • kernel-rt AlmaLinux 9 5.14.0-503.19.1.el9_5
  • kernel-64k AlmaLinux 9 5.14.0-503.19.1.el9_5

almalinux advisories ALSA-2024:11486ALSA-2024:10281

  • kernel Rocky Linux 8 4.18.0-553.30.1.el8_10

rocky linux advisories RLSA-2024:10281

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-2024-27399 updated cvss 5.5

kernel: Bluetooth: l2cap: fix null-ptr-deref in l2cap_chan_timeout

  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +6 more
    affected: no fix planned “Will not fix”
  • 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: no fix available
  • Red Hat CodeReady Linux Builder (v. 9) libperf 5.14.0-503.19.1.el9_5, kernel-debuginfo-common-s390x 5.14.0-503.19.1.el9_5, kernel-debuginfo-common-x86_64 5.14.0-503.19.1.el9_5, kernel-debuginfo-common-aarch64 5.14.0-503.19.1.el9_5, kernel-debuginfo-common-ppc64le 5.14.0-503.19.1.el9_5
    fixed: vendor fix RHSA-2024:11486
  • Red Hat CodeReady Linux Builder EUS (v.8.8) kernel-debuginfo-common-x86_64 4.18.0-477.74.1.el8_8, kernel-debuginfo-common-aarch64 4.18.0-477.74.1.el8_8, kernel-debuginfo-common-ppc64le 4.18.0-477.74.1.el8_8
    fixed: vendor fix RHSA-2024:6993
  • Red Hat CodeReady Linux Builder EUS (v.9.2) kernel-debuginfo-common-s390x 5.14.0-284.95.1.el9_2, kernel-debuginfo-common-x86_64 5.14.0-284.95.1.el9_2, kernel-debuginfo-common-aarch64 5.14.0-284.95.1.el9_2, kernel-debuginfo-common-ppc64le 5.14.0-284.95.1.el9_2
    fixed: vendor fix RHSA-2024:10772
  • Red Hat CodeReady Linux Builder EUS (v.9.4) libperf 5.14.0-427.47.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.47.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.47.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.47.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.47.1.el9_4
    fixed: vendor fix RHSA-2024:10771
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-503.19.1.el9_5, perf 5.14.0-503.19.1.el9_5, rtla 5.14.0-503.19.1.el9_5, kernel-devel-matched 5.14.0-503.19.1.el9_5, kernel-64k-devel-matched 5.14.0-503.19.1.el9_5, kernel-debug-devel-matched 5.14.0-503.19.1.el9_5, +6 more
    fixed: vendor fix RHSA-2024:11486
show 15 more
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) perf 5.14.0-284.95.1.el9_2, rtla 5.14.0-284.95.1.el9_2, kernel-devel-matched 5.14.0-284.95.1.el9_2, kernel-64k-devel-matched 5.14.0-284.95.1.el9_2, kernel-debug-devel-matched 5.14.0-284.95.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.95.1.el9_2, +5 more
    fixed: vendor fix RHSA-2024:10772
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.47.1.el9_4, perf 5.14.0-427.47.1.el9_4, rtla 5.14.0-427.47.1.el9_4, kernel-devel-matched 5.14.0-427.47.1.el9_4, kernel-64k-devel-matched 5.14.0-427.47.1.el9_4, kernel-debug-devel-matched 5.14.0-427.47.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:10771
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.30.1.el8_10, kernel 4.18.0-553.30.1.el8_10, bpftool 4.18.0-553.30.1.el8_10, kernel-core 4.18.0-553.30.1.el8_10, kernel-tools 4.18.0-553.30.1.el8_10, python3-perf 4.18.0-553.30.1.el8_10, +15 more
    fixed: vendor fix RHSA-2024:10281
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.4.0-503.19.1.el9_5, kernel 5.14.0-503.19.1.el9_5, kernel-64k 5.14.0-503.19.1.el9_5, kernel-core 5.14.0-503.19.1.el9_5, kernel-tools 5.14.0-503.19.1.el9_5, python3-perf 5.14.0-503.19.1.el9_5, +29 more
    fixed: vendor fix RHSA-2024:11486
  • Red Hat Enterprise Linux BaseOS EUS (v.8.8) perf 4.18.0-477.74.1.el8_8, kernel 4.18.0-477.74.1.el8_8, bpftool 4.18.0-477.74.1.el8_8, kernel-core 4.18.0-477.74.1.el8_8, kernel-tools 4.18.0-477.74.1.el8_8, python3-perf 4.18.0-477.74.1.el8_8, +15 more
    fixed: vendor fix RHSA-2024:6993
  • Red Hat Enterprise Linux BaseOS EUS (v.9.2) bpftool 7.0.0-284.95.1.el9_2, kernel 5.14.0-284.95.1.el9_2, kernel-64k 5.14.0-284.95.1.el9_2, kernel-core 5.14.0-284.95.1.el9_2, kernel-tools 5.14.0-284.95.1.el9_2, python3-perf 5.14.0-284.95.1.el9_2, +28 more
    fixed: vendor fix RHSA-2024:10772
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool 7.3.0-427.47.1.el9_4, kernel 5.14.0-427.47.1.el9_4, kernel-64k 5.14.0-427.47.1.el9_4, kernel-core 5.14.0-427.47.1.el9_4, kernel-tools 5.14.0-427.47.1.el9_4, python3-perf 5.14.0-427.47.1.el9_4, +28 more
    fixed: vendor fix RHSA-2024:10771
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.30.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.30.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.30.1.el8_10
    fixed: vendor fix RHSA-2024:10281
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-503.19.1.el9_5, kernel-rt-core 5.14.0-503.19.1.el9_5, kernel-rt-modules 5.14.0-503.19.1.el9_5, kernel-rt-debug-core 5.14.0-503.19.1.el9_5, kernel-rt-modules-core 5.14.0-503.19.1.el9_5, kernel-rt-debug-modules 5.14.0-503.19.1.el9_5, +4 more
    fixed: vendor fix RHSA-2024:11486
  • Red Hat Enterprise Linux Real Time EUS (v.9.2) kernel-rt 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-core 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-modules 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-debug-core 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-modules-core 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-debug-modules 5.14.0-284.95.1.rt14.380.el9_2, +4 more
    fixed: vendor fix RHSA-2024:10773
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.47.1.el9_4, kernel-rt-core 5.14.0-427.47.1.el9_4, kernel-rt-modules 5.14.0-427.47.1.el9_4, kernel-rt-debug-core 5.14.0-427.47.1.el9_4, kernel-rt-modules-core 5.14.0-427.47.1.el9_4, kernel-rt-debug-modules 5.14.0-427.47.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:10771
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-503.19.1.el9_5, kernel-rt-kvm 5.14.0-503.19.1.el9_5, kernel-rt-core 5.14.0-503.19.1.el9_5, kernel-rt-modules 5.14.0-503.19.1.el9_5, kernel-rt-debug-kvm 5.14.0-503.19.1.el9_5, kernel-rt-debug-core 5.14.0-503.19.1.el9_5, +6 more
    fixed: vendor fix RHSA-2024:11486
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.2) kernel-rt 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-kvm 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-core 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-modules 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-debug-kvm 5.14.0-284.95.1.rt14.380.el9_2, kernel-rt-debug-core 5.14.0-284.95.1.rt14.380.el9_2, +6 more
    fixed: vendor fix RHSA-2024:10773
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.47.1.el9_4, kernel-rt-kvm 5.14.0-427.47.1.el9_4, kernel-rt-core 5.14.0-427.47.1.el9_4, kernel-rt-modules 5.14.0-427.47.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.47.1.el9_4, kernel-rt-debug-core 5.14.0-427.47.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:10771
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux AppStream EUS (v.9.2) kernel-doc 5.14.0-284.95.1.el9_2
    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
partial
Assessed
2 y ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

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.