{"id":"CVE-2026-43232","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-43232","generatedAt":"2026-10-28T02:10:39.873Z","title":"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().","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: wan: farsync: Fix use-after-free bugs caused by unfinished tasklets\n\nWhen the FarSync T-series card is being detached, the fst_card_info is\ndeallocated in fst_remove_one(). However, the fst_tx_task or fst_int_task\nmay still be running or pending, leading to use-after-free bugs when the\nalready freed fst_card_info is accessed in fst_process_tx_work_q() or\nfst_process_int_work_q().\n\nA typical race condition is depicted below:\n\nCPU 0 (cleanup)           | CPU 1 (tasklet)\n                          | fst_start_xmit()\nfst_remove_one()          |   tasklet_schedule()\n  unregister_hdlc_device()|\n                          | fst_process_tx_work_q() //handler\n  kfree(card) //free      |   do_bottom_half_tx()\n                          |     card-> //use\n\nThe following KASAN trace was captured:\n\n==================================================================\n BUG: KASAN: slab-use-after-free in do_bottom_half_tx+0xb88/0xd00\n Read of size 4 at addr ffff88800aad101c by task ksoftirqd/3/32\n ...\n Call Trace:\n  <IRQ>\n  dump_stack_lvl+0x55/0x70\n  print_report+0xcb/0x5d0\n  ? do_bottom_half_tx+0xb88/0xd00\n  kasan_report+0xb8/0xf0\n  ? do_bottom_half_tx+0xb88/0xd00\n  do_bottom_half_tx+0xb88/0xd00\n  ? _raw_spin_lock_irqsave+0x85/0xe0\n  ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n  ? __pfx___hrtimer_run_queues+0x10/0x10\n  fst_process_tx_work_q+0x67/0x90\n  tasklet_action_common+0x1fa/0x720\n  ? hrtimer_interrupt+0x31f/0x780\n  handle_softirqs+0x176/0x530\n  __irq_exit_rcu+0xab/0xe0\n  sysvec_apic_timer_interrupt+0x70/0x80\n ...\n\n Allocated by task 41 on cpu 3 at 72.330843s:\n  kasan_save_stack+0x24/0x50\n  kasan_save_track+0x17/0x60\n  __kasan_kmalloc+0x7f/0x90\n  fst_add_one+0x1a5/0x1cd0\n  local_pci_probe+0xdd/0x190\n  pci_device_probe+0x341/0x480\n  really_probe+0x1c6/0x6a0\n  __driver_probe_device+0x248/0x310\n  driver_probe_device+0x48/0x210\n  __device_attach_driver+0x160/0x320\n  bus_for_each_drv+0x101/0x190\n  __device_attach+0x198/0x3a0\n  device_initial_probe+0x78/0xa0\n  pci_bus_add_device+0x81/0xc0\n  pci_bus_add_devices+0x7e/0x190\n  enable_slot+0x9b9/0x1130\n  acpiphp_check_bridge.part.0+0x2e1/0x460\n  acpiphp_hotplug_notify+0x36c/0x3c0\n  acpi_device_hotplug+0x203/0xb10\n  acpi_hotplug_work_fn+0x59/0x80\n ...\n\n Freed by task 41 on cpu 1 at 75.138639s:\n  kasan_save_stack+0x24/0x50\n  kasan_save_track+0x17/0x60\n  kasan_save_free_info+0x3b/0x60\n  __kasan_slab_free+0x43/0x70\n  kfree+0x135/0x410\n  fst_remove_one+0x2ca/0x540\n  pci_device_remove+0xa6/0x1d0\n  device_release_driver_internal+0x364/0x530\n  pci_stop_bus_device+0x105/0x150\n  pci_stop_and_remove_bus_device+0xd/0x20\n  disable_slot+0x116/0x260\n  acpiphp_disable_and_eject_slot+0x4b/0x190\n  acpiphp_hotplug_notify+0x230/0x3c0\n  acpi_device_hotplug+0x203/0xb10\n  acpi_hotplug_work_fn+0x59/0x80\n ...\n\n The buggy address belongs to the object at ffff88800aad1000\n  which belongs to the cache kmalloc-1k of size 1024\n The buggy address is located 28 bytes inside of\n  freed 1024-byte region\n The buggy address belongs to the physical page:\n page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xaad0\n head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0\n flags: 0x100000000000040(head|node=0|zone=1)\n page_type: f5(slab)\n raw: 0100000000000040 ffff888007042dc0 dead000000000122 0000000000000000\n raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000\n head: 0100000000000040 ffff888007042dc0 dead000000000122 0000000000000000\n head: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000\n head: 0100000000000003 ffffea00002ab401 00000000ffffffff 00000000ffffffff\n head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n  ffff88800aad0f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\n  ffff88800aad0f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc\n >ffff88800aad1000: fa fb\n---truncated---","published":"2026-05-06T12:16:43.000Z","lastModified":"2026-06-17T10:49:12.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},"cwe":["CWE-416"],"affected":["linux/linux kernel"],"epss":{"score":0.00387,"percentile":0.32509,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.39%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/04edfdfdfcdefc02408ab670607261b0a0a9a02e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/086131807d119238cd464e5b0845e48d938dfd79","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/200bdb8d367ca9b478f9c56ebe56411604d55c81","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/21d341fe514fd07e345ed264c9eee21cb2061ca2","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/337d7b4112a47984ee319171b75b73bab47e7924","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ae894e47e1cd5a6bf8a0423d888c45df8b2b02dc","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bae8a5d2e759da2e0cba33ab2080deee96a09373","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cac048ebfbb92d91d719f74b59177cb70a7633b8","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43232","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}