batman-adv: bypass empty buckets in batadv_purge_orig_ref()
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-667 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: batman-adv: bypass empty buckets in batadv_purge_orig_ref() Many syzbot reports are pointing to soft lockups in batadv_purge_orig_ref() [1] Root cause is unknown, but we can avoid spending too much time there and perhaps get more interesting reports. [1] watchdog: BUG: soft lockup - CPU#0 stuck for 27s! [kworker/u4:6:621] Modules linked in: irq event stamp: 6182794 hardirqs last enabled at (6182793): [<ffff8000801dae10>] __local_bh_enable_ip+0x224/0x44c kernel/softirq.c:386 hardirqs last disabled at (6182794): [<ffff80008ad66a78>] __el1_irq arch/arm64/kernel/entry-common.c:533 [inline] hardirqs last disabled at (6182794): [<ffff80008ad66a78>] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:551 softirqs last enabled at (6182792): [<ffff80008aab71c4>] spin_unlock_bh include/linux/spinlock.h:396 [inline] softirqs last enabled at (6182792): [<ffff80008aab71c4>] batadv_purge_orig_ref+0x114c/0x1228 net/batman-adv/originator.c:1287 softirqs last disabled at (6182790): [<ffff80008aab61dc>] spin_lock_bh include/linux/spinlock.h:356 [inline] softirqs last disabled at (6182790): [<ffff80008aab61dc>] batadv_purge_orig_ref+0x164/0x1228 net/batman-adv/originator.c:1271 CPU: 0 PID: 621 Comm: kworker/u4:6 Not tainted 6.8.0-rc7-syzkaller-g707081b61156 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 Workqueue: bat_events batadv_purge_orig pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : should_resched arch/arm64/include/asm/preempt.h:79 [inline] pc : __local_bh_enable_ip+0x228/0x44c kernel/softirq.c:388 lr : __local_bh_enable_ip+0x224/0x44c kernel/softirq.c:386 sp : ffff800099007970 x29: ffff800099007980 x28: 1fffe00018fce1bd x27: dfff800000000000 x26: ffff0000d2620008 x25: ffff0000c7e70de8 x24: 0000000000000001 x23: 1fffe00018e57781 x22: dfff800000000000 x21: ffff80008aab71c4 x20: ffff0001b40136c0 x19: ffff0000c72bbc08 x18: 1fffe0001a817bb0 x17: ffff800125414000 x16: ffff80008032116c x15: 0000000000000001 x14: 1fffe0001ee9d610 x13: 0000000000000000 x12: 0000000000000003 x11: 0000000000000000 x10: 0000000000ff0100 x9 : 0000000000000000 x8 : 00000000005e5789 x7 : ffff80008aab61dc x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000000 x2 : 0000000000000006 x1 : 0000000000000080 x0 : ffff800125414000 Call trace: __daif_local_irq_enable arch/arm64/include/asm/irqflags.h:27 [inline] arch_local_irq_enable arch/arm64/include/asm/irqflags.h:49 [inline] __local_bh_enable_ip+0x228/0x44c kernel/softirq.c:386 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock_bh+0x3c/0x4c kernel/locking/spinlock.c:210 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_purge_orig_ref+0x114c/0x1228 net/batman-adv/originator.c:1287 batadv_purge_orig+0x20/0x70 net/batman-adv/originator.c:1300 process_one_work+0x694/0x1204 kernel/workqueue.c:2633 process_scheduled_works kernel/workqueue.c:2706 [inline] worker_thread+0x938/0xef4 kernel/workqueue.c:2787 kthread+0x288/0x310 kernel/kthread.c:388 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0-rc7-syzkaller-g707081b61156 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : arch_local_irq_enable+0x8/0xc arch/arm64/include/asm/irqflags.h:51 lr : default_idle_call+0xf8/0x128 kernel/sched/idle.c:103 sp : ffff800093a17d30 x29: ffff800093a17d30 x28: dfff800000000000 x27: 1ffff00012742fb4 x26: ffff80008ec9d000 x25: 0000000000000000 x24: 0000000000000002 x23: 1ffff00011d93a74 x22: ffff80008ec9d3a0 x21: 0000000000000000 x20: ffff0000c19dbc00 x19: ffff8000802d0fd8 x18: 1fffe00036804396 x17: ffff80008ec9d000 x16: ffff8000802d089c x15: 0000000000000001 ---truncated---
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.39 and later | 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.39 and later Fixed in 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | before 4.19.317; 4.20 to before 5.4.279; 5.5 to before 5.10.221; 5.11 to before 5.15.162; 5.16 to before 6.1.96; 6.2 to before 6.6.36; 6.7 to before 6.9.7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions before 4.19.317; 4.20 to before 5.4.279; 5.5 to before 5.10.221; 5.11 to before 5.15.162; 5.16 to before 6.1.96; 6.2 to before 6.6.36; 6.7 to before 6.9.7 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2024-40981
- 2026-10-03 Alias added: GHSA-66mx-vw67-wmq9
References
Patch 8
- https://git.kernel.org/stable/c/79636f636126775436a11ee9cf00a9253a33ac11
- https://git.kernel.org/stable/c/154e3f862ba33675cf3f4abf0a0a309a89df87d2
- https://git.kernel.org/stable/c/82cdea8f3af1e36543c937df963d108c60bea030
- https://git.kernel.org/stable/c/92176caf9896572f00e741a93cecc0ef1172da07
- https://git.kernel.org/stable/c/fed7914858a1f1f3e6350bb0f620d6ef15107d16
- https://git.kernel.org/stable/c/2685008a5f9a636434a8508419cee8158a2f52c8
- https://git.kernel.org/stable/c/ae7f3cffe86aea3da0e8e079525a1ae619b8862a
- https://git.kernel.org/stable/c/40dc8ab605894acae1473e434944924a22cfaaa0
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- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2024-40981 · CVE Program
- CVE-2024-40981 · NVD
- FIRST EPSS
- GHSA-66mx-vw67-wmq9 · GitHub Advisory Database · CC BY 4.0
- CVE-2024-40981 · Red Hat security data · CC BY 4.0
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