CVE-2026-43232

Description

In the Linux kernel, the following vulnerability has been resolved: net: wan: farsync: Fix use-after-free bugs caused by unfinished tasklets When the FarSync T-series card is being detached, the fst_card_info is deallocated in fst_remove_one(). However, the fst_tx_task or fst_int_task may still be running or pending, leading to use-after-free bugs when the already freed fst_card_info is accessed in fst_process_tx_work_q() or fst_process_int_work_q(). A typical race condition is depicted below: CPU 0 (cleanup) | CPU 1 (tasklet) | fst_start_xmit() fst_remove_one() | tasklet_schedule() unregister_hdlc_device()| | fst_process_tx_work_q() //handler kfree(card) //free | do_bottom_half_tx() | card-> //use The following KASAN trace was captured: ================================================================== BUG: KASAN: slab-use-after-free in do_bottom_half_tx+0xb88/0xd00 Read of size 4 at addr ffff88800aad101c by task ksoftirqd/3/32 ... Call Trace: <IRQ> dump_stack_lvl+0x55/0x70 print_report+0xcb/0x5d0 ? do_bottom_half_tx+0xb88/0xd00 kasan_report+0xb8/0xf0 ? do_bottom_half_tx+0xb88/0xd00 do_bottom_half_tx+0xb88/0xd00 ? _raw_spin_lock_irqsave+0x85/0xe0 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? __pfx___hrtimer_run_queues+0x10/0x10 fst_process_tx_work_q+0x67/0x90 tasklet_action_common+0x1fa/0x720 ? hrtimer_interrupt+0x31f/0x780 handle_softirqs+0x176/0x530 __irq_exit_rcu+0xab/0xe0 sysvec_apic_timer_interrupt+0x70/0x80 ... Allocated by task 41 on cpu 3 at 72.330843s: kasan_save_stack+0x24/0x50 kasan_save_track+0x17/0x60 __kasan_kmalloc+0x7f/0x90 fst_add_one+0x1a5/0x1cd0 local_pci_probe+0xdd/0x190 pci_device_probe+0x341/0x480 really_probe+0x1c6/0x6a0 __driver_probe_device+0x248/0x310 driver_probe_device+0x48/0x210 __device_attach_driver+0x160/0x320 bus_for_each_drv+0x101/0x190 __device_attach+0x198/0x3a0 device_initial_probe+0x78/0xa0 pci_bus_add_device+0x81/0xc0 pci_bus_add_devices+0x7e/0x190 enable_slot+0x9b9/0x1130 acpiphp_check_bridge.part.0+0x2e1/0x460 acpiphp_hotplug_notify+0x36c/0x3c0 acpi_device_hotplug+0x203/0xb10 acpi_hotplug_work_fn+0x59/0x80 ... Freed by task 41 on cpu 1 at 75.138639s: kasan_save_stack+0x24/0x50 kasan_save_track+0x17/0x60 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x43/0x70 kfree+0x135/0x410 fst_remove_one+0x2ca/0x540 pci_device_remove+0xa6/0x1d0 device_release_driver_internal+0x364/0x530 pci_stop_bus_device+0x105/0x150 pci_stop_and_remove_bus_device+0xd/0x20 disable_slot+0x116/0x260 acpiphp_disable_and_eject_slot+0x4b/0x190 acpiphp_hotplug_notify+0x230/0x3c0 acpi_device_hotplug+0x203/0xb10 acpi_hotplug_work_fn+0x59/0x80 ... The buggy address belongs to the object at ffff88800aad1000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 28 bytes inside of freed 1024-byte region The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xaad0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x100000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0100000000000040 ffff888007042dc0 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000 head: 0100000000000040 ffff888007042dc0 dead000000000122 0000000000000000 head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000 head: 0100000000000003 ffffea00002ab401 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88800aad0f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88800aad0f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88800aad1000: fa fb ---truncated---

Gravité et risque d'exploitation

CVE-2026-43232 obtient un score CVSS de 8.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.58 %, ce qui la place devant 46.5 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <04edfdfdfcdefc02408ab670607261b0a0a9a02e, 024d2a7c8ee5bfe14357f20cf1bbbbcc5d228cc9, 51e2d1b84acac39f79cacb60e6e154ce00a9d308, <cac048ebfbb92d91d719f74b59177cb70a7633b8, 0, <6.1.165, 7.0, 41798a063fd4721b609e11ad839b6820f5070ca7, <4.10, b1fe377b43c405b169cffd1b3aa39c1dde16f3ed, <086131807d119238cd464e5b0845e48d938dfd79, 4.14.303, 6.1.165, 6.12.75, ce9dc768767bbe73d2dd330a9075e849cb8a84d4, <337d7b4112a47984ee319171b75b73bab47e7924, 4.19.270, <4.20, <=5.10.*, <=6.6.*, <ae894e47e1cd5a6bf8a0423d888c45df8b2b02dc, <200bdb8d367ca9b478f9c56ebe56411604d55c81, 5.4.229, <=6.19.*, 6.0.16, <5.10.252, <6.1, 998b4e54f517961d3d75144c088a24423e003005, <5.5, <=6.18.*, 2f623aaf9f31de968dea6169849706a2f9be444c, <6.2, 4.9.337, 6.6.128, 6.19.6, 5.10.252, <21d341fe514fd07e345ed264c9eee21cb2061ca2, 5.10.163, 6.18.16, <=*, <=5.15.*, 6.1.2, <bae8a5d2e759da2e0cba33ab2080deee96a09373, 0c5f2c7700cb18aeab1574588d3bb9c0454bf228, <4.15, 5.15.202, bb1715a6bfb0c57a68524732a376498a2569f016, <5.15.202, 6.2, 5.15.86) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/cac048ebfbb92d91d719f74b59177cb70a7633b8
• https://git.kernel.org/stable/c/086131807d119238cd464e5b0845e48d938dfd79
• https://git.kernel.org/stable/c/ae894e47e1cd5a6bf8a0423d888c45df8b2b02dc
• https://git.kernel.org/stable/c/337d7b4112a47984ee319171b75b73bab47e7924
• https://git.kernel.org/stable/c/200bdb8d367ca9b478f9c56ebe56411604d55c81
• https://git.kernel.org/stable/c/21d341fe514fd07e345ed264c9eee21cb2061ca2
• https://git.kernel.org/stable/c/04edfdfdfcdefc02408ab670607261b0a0a9a02e
• https://git.kernel.org/stable/c/bae8a5d2e759da2e0cba33ab2080deee96a09373