Cloudanix VulnDB

CVE-2024-44934

None

CVSS

—

EPSS

0.2%

Published

Aug 26, 2024

CISA due date

—

Cloudanix analysis

Monitor only SSVC: Track

A bug in Linux network bridging code can let an attacker crash the system or potentially run code by removing network ports while certain group timers are still active.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Privilege Gain
Component
OS kernel
Class
Use After Free
Remediation
Patch
Effort
Medium
Patch risk
Low

What it actually does

Use-after-free in bridge multicast code where a port can be freed while group timers from prior GC cycles are still active, because flush_work is not called before port removal.

Why it matters to the business

Kernel instability or potential code execution on systems using Linux bridging with multicast, increasing crash risk and maintenance overhead for affected deployments.

How an attack unfolds

An attacker triggers concurrent bridge port removal and multicast GC cycles so that a timer expires after the port structure has been freed, leading to a read of freed memory in br_multicast_port_group_expired.

How to fix it

Apply the upstream fix in commit 1e16828020c674b3be85f52685e8b80f9008f50f or update to a kernel release containing it; rebuild and reboot affected systems.

How to confirm the fix worked

Confirm the presence of flush_work before port freeing in br_multicast.c and test with syzkaller-style reproducers that previously triggered the KASAN report.

Typical attack path

  1. Create and configure a bridge interface with multicast snooping enabled
  2. Add and then remove a port while multicast groups have active timers
  3. Force scheduling of GC work and timer expiration on the now-freed port structure

How to detect it

Search kernel logs and KASAN reports for br_multicast_port_group_expired and slab-use-after-free involving bridge port structures; correlate with bridge port deletion events.

What your security team should do

  • Prioritize kernel updates on all systems exposing bridge interfaces
  • Review network configurations that enable multicast snooping on bridges
  • Monitor for unexplained kernel oops or KASAN reports involving br_multicast

The record

In the Linux kernel, the following vulnerability has been resolved: net: bridge: mcast: wait for previous gc cycles when removing port syzbot hit a use-after-free[1] which is caused because the bridge doesn't make sure that all previous garbage has been collected when removing a port. What happens is: CPU 1 CPU 2 start gc cycle remove port acquire gc lock first wait for lock call br_multicasg_gc() directly acquire lock now but free port the port can be freed while grp timers still running Make sure all previous gc cycles have finished by using flush_work before freeing the port. [1] BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699 CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792 expire_timers kernel/time/timer.c:1843 [inline] __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437

Affected packages

Ecosystem Package Introduced Fixed
Debian:11 linux 0 No fix
Debian:11 linux-6.1 0 6.1.119-1~deb11u1
Debian:12 linux 0 6.1.106-1
Debian:13 linux 0 6.10.6-1
Linux Kernel 5.10.0 5.15.165
Mageia:9 kernel 0 6.6.50-1.mga9
Mageia:9 kernel-linus 0 6.6.50-1.mga9
Mageia:9 kmod-virtualbox 0 7.0.20-53.mga9
Mageia:9 kmod-xtables-addons 0 3.24-61.mga9
SUSE:Linux Enterprise High Availability Extension 15 SP6 kernel-default 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-64kb 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-default 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-default-base 0 5.14.21-150500.55.91.1.150500.6.41.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-docs 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-obs-build 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-source 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-syms 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-64kb 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-default 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-default-base 0 5.14.21-150500.55.91.1.150500.6.41.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-docs 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-obs-build 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-source 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-syms 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Live Patching 15 SP5 kernel-default 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Live Patching 15 SP5 kernel-livepatch-SLE15-SP5_Update_22 0 1-150500.11.3.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-default 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_7 0 1-150600.1.3.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_7 0 1-150600.13.3.1
SUSE:Linux Enterprise Micro 5.5 kernel-default 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Micro 5.5 kernel-default-base 0 5.14.21-150500.55.91.1.150500.6.41.1
SUSE:Linux Enterprise Micro 5.5 kernel-rt 0 5.14.21-150500.13.82.1
SUSE:Linux Enterprise Micro 5.5 kernel-source-rt 0 5.14.21-150500.13.82.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-64kb 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default-base 0 6.4.0-150600.23.33.1.150600.12.14.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-source 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-zfcpdump 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-coco 0 6.4.0-15061.12.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-coco_debug 0 6.4.0-15061.12.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-source-coco 0 6.4.0-15061.12.coco15sp6.1
SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 kernel-syms-coco 0 6.4.0-15061.12.coco15sp6.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-docs 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-obs-build 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-source 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-syms 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Legacy 15 SP6 kernel-default 0 6.4.0-150600.23.33.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-azure 0 6.4.0-150600.8.23.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-source-azure 0 6.4.0-150600.8.23.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-syms-azure 0 6.4.0-150600.8.23.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-64kb 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-default 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-default-base 0 5.14.21-150500.55.91.1.150500.6.41.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-docs 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-obs-build 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-source 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-syms 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server 15 SP5-LTSS kernel-zfcpdump 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-default 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-default-base 0 5.14.21-150500.55.91.1.150500.6.41.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-docs 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-obs-build 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-source 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Server for SAP Applications 15 SP5 kernel-syms 0 5.14.21-150500.55.91.1
SUSE:Linux Enterprise Workstation Extension 15 SP6 kernel-default 0 6.4.0-150600.23.33.1
SUSE:Real Time Module 15 SP6 kernel-rt 0 6.4.0-150600.10.23.1
SUSE:Real Time Module 15 SP6 kernel-rt_debug 0 6.4.0-150600.10.23.1
SUSE:Real Time Module 15 SP6 kernel-source-rt 0 6.4.0-150600.10.23.1
SUSE:Real Time Module 15 SP6 kernel-syms-rt 0 6.4.0-150600.10.23.1
Ubuntu:14.04:LTS linux 0 3.11.0-12.19
Ubuntu:14.04:LTS linux-aws 0 4.4.0-1002.2
Ubuntu:14.04:LTS linux-azure 0 4.15.0-1023.24~14.04.1
Ubuntu:14.04:LTS linux-lts-xenial 0 4.4.0-13.29~14.04.1
Ubuntu:16.04:LTS linux 0 4.4.0-2.16
Ubuntu:16.04:LTS linux-aws 0 4.4.0-1001.10
Ubuntu:16.04:LTS linux-aws-hwe 0 4.15.0-1030.31~16.04.1
Ubuntu:16.04:LTS linux-azure 0 4.11.0-1009.9
Ubuntu:16.04:LTS linux-gcp 0 4.10.0-1004.4
Ubuntu:16.04:LTS linux-hwe 0 4.8.0-39.42~16.04.1
Ubuntu:16.04:LTS linux-hwe-edge 0 No fix
Ubuntu:16.04:LTS linux-kvm 0 4.4.0-1004.9
Ubuntu:16.04:LTS linux-oracle 0 4.15.0-1007.9~16.04.1
Ubuntu:18.04:LTS linux 0 4.13.0-16.19
Ubuntu:18.04:LTS linux-aws 0 4.15.0-1001.1
Ubuntu:18.04:LTS linux-aws-5.0 0 No fix
Ubuntu:18.04:LTS linux-aws-5.3 0 No fix
Ubuntu:18.04:LTS linux-aws-5.4 0 5.4.0-1018.18~18.04.1
Ubuntu:18.04:LTS linux-azure 0 No fix
Ubuntu:18.04:LTS linux-azure-4.15 0 4.15.0-1082.92
Ubuntu:18.04:LTS linux-azure-5.3 0 No fix
Ubuntu:18.04:LTS linux-azure-5.4 0 5.4.0-1020.20~18.04.1
Ubuntu:18.04:LTS linux-azure-edge 0 No fix
Ubuntu:18.04:LTS linux-gcp 0 No fix
Ubuntu:18.04:LTS linux-gcp-4.15 0 4.15.0-1071.81
Ubuntu:18.04:LTS linux-gcp-5.3 0 No fix
Ubuntu:18.04:LTS linux-gcp-5.4 0 5.4.0-1019.19~18.04.2
Ubuntu:18.04:LTS linux-gke-4.15 0 No fix
Ubuntu:18.04:LTS linux-gke-5.4 0 No fix
Ubuntu:18.04:LTS linux-gkeop-5.4 0 No fix
Ubuntu:18.04:LTS linux-hwe 0 No fix
Ubuntu:18.04:LTS linux-hwe-5.4 0 5.4.0-37.41~18.04.1
Ubuntu:18.04:LTS linux-hwe-edge 0 5.0.0-15.16~18.04.1
Ubuntu:18.04:LTS linux-ibm-5.4 0 5.4.0-1010.11~18.04.2
Ubuntu:18.04:LTS linux-kvm 0 4.15.0-1002.2
Ubuntu:18.04:LTS linux-oem 0 No fix
Ubuntu:18.04:LTS linux-oracle 0 4.15.0-1007.9
Ubuntu:18.04:LTS linux-oracle-5.0 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.3 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.4 0 5.4.0-1019.19~18.04.1
Ubuntu:18.04:LTS linux-raspi-5.4 0 5.4.0-1013.13~18.04.1
Ubuntu:20.04:LTS linux 0 5.4.0-9.12
Ubuntu:20.04:LTS linux-aws 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-aws-5.11 0 No fix
Ubuntu:20.04:LTS linux-aws-5.13 0 No fix
Ubuntu:20.04:LTS linux-aws-5.15 0 5.15.0-1072.78~20.04.1
Ubuntu:20.04:LTS linux-aws-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure 0 5.4.0-1006.6
Ubuntu:20.04:LTS linux-azure-5.11 0 No fix
Ubuntu:20.04:LTS linux-azure-5.13 0 No fix
Ubuntu:20.04:LTS linux-azure-5.15 0 5.15.0-1078.87~20.04.1
Ubuntu:20.04:LTS linux-azure-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure-fde 0 No fix
Ubuntu:20.04:LTS linux-azure-fde-5.15 0 No fix
Ubuntu:20.04:LTS linux-bluefield 0 5.4.0-1007.10
Ubuntu:20.04:LTS linux-gcp 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-gcp-5.11 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.13 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.15 0 5.15.0-1071.79~20.04.1
Ubuntu:20.04:LTS linux-gcp-5.8 0 No fix
Ubuntu:20.04:LTS linux-gke 0 No fix
Ubuntu:20.04:LTS linux-gke-5.15 0 No fix
Ubuntu:20.04:LTS linux-gkeop 0 5.4.0-1008.9
Ubuntu:20.04:LTS linux-gkeop-5.15 0 5.15.0-1055.62~20.04.1
Ubuntu:20.04:LTS linux-hwe-5.11 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.13 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.15 0 5.15.0-125.135~20.04.1
Ubuntu:20.04:LTS linux-hwe-5.8 0 No fix
Ubuntu:20.04:LTS linux-ibm 0 5.4.0-1003.4
Ubuntu:20.04:LTS linux-ibm-5.15 0 5.15.0-1065.68~20.04.1
Ubuntu:20.04:LTS linux-intel-5.13 0 No fix
Ubuntu:20.04:LTS linux-intel-iotg-5.15 0 5.15.0-1067.73~20.04.1
Ubuntu:20.04:LTS linux-iot 0 5.4.0-1001.3
Ubuntu:20.04:LTS linux-kvm 0 5.4.0-1004.4
Ubuntu:20.04:LTS linux-lowlatency-hwe-5.15 0 5.15.0-125.135~20.04.1
Ubuntu:20.04:LTS linux-nvidia-tegra-5.15 0 5.15.0-1032.32~20.04.1
Ubuntu:20.04:LTS linux-oem-5.10 0 No fix
Ubuntu:20.04:LTS linux-oem-5.13 0 No fix
Ubuntu:20.04:LTS linux-oem-5.14 0 No fix
Ubuntu:20.04:LTS linux-oem-5.6 0 No fix
Ubuntu:20.04:LTS linux-oracle 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-oracle-5.11 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.13 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.15 0 5.15.0-1070.76~20.04.1
Ubuntu:20.04:LTS linux-oracle-5.8 0 No fix
Ubuntu:20.04:LTS linux-raspi 0 5.4.0-1007.7
Ubuntu:20.04:LTS linux-raspi2 0 No fix
Ubuntu:20.04:LTS linux-riscv 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.11 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.15 0 5.15.0-1068.72~20.04.1
Ubuntu:20.04:LTS linux-riscv-5.8 0 No fix
Ubuntu:20.04:LTS linux-xilinx-zynqmp 0 5.4.0-1020.24
Ubuntu:22.04:LTS linux 0 5.15.0-125.135
Ubuntu:22.04:LTS linux-allwinner-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws 0 5.15.0-1072.78
Ubuntu:22.04:LTS linux-aws-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws-6.2 0 No fix
Ubuntu:22.04:LTS linux-aws-6.5 0 No fix
Ubuntu:22.04:LTS linux-aws-6.8 0 6.8.0-1020.22~22.04.1
Ubuntu:22.04:LTS linux-azure 0 5.15.0-1075.84
Ubuntu:22.04:LTS linux-azure-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-6.2 0 No fix
Ubuntu:22.04:LTS linux-azure-6.5 0 No fix
Ubuntu:22.04:LTS linux-azure-6.8 0 6.8.0-1020.23~22.04.1
Ubuntu:22.04:LTS linux-azure-fde 0 No fix
Ubuntu:22.04:LTS linux-azure-fde-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-fde-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp 0 5.15.0-1071.79
Ubuntu:22.04:LTS linux-gcp-5.19 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.5 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.8 0 6.8.0-1019.21~22.04.1
Ubuntu:22.04:LTS linux-gke 0 5.15.0-1069.75
Ubuntu:22.04:LTS linux-gkeop 0 5.15.0-1055.62
Ubuntu:22.04:LTS linux-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.5 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.8 0 6.8.0-50.51~22.04.1
Ubuntu:22.04:LTS linux-ibm 0 5.15.0-1065.68
Ubuntu:22.04:LTS linux-ibm-6.8 0 6.8.0-1017.17~22.04.1
Ubuntu:22.04:LTS linux-intel-iot-realtime 0 No fix
Ubuntu:22.04:LTS linux-intel-iotg 0 5.15.0-1067.73
Ubuntu:22.04:LTS linux-kvm 0 5.15.0-1069.74
Ubuntu:22.04:LTS linux-lowlatency 0 5.15.0-125.135
Ubuntu:22.04:LTS linux-lowlatency-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.5 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.8 0 6.8.0-50.51.1~22.04.1
Ubuntu:22.04:LTS linux-nvidia 0 5.15.0-1067.68
Ubuntu:22.04:LTS linux-nvidia-6.2 0 No fix
Ubuntu:22.04:LTS linux-nvidia-6.5 0 No fix

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