CVE-2022-49985

Estado: ModificadaAlta (7.1)—

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

bpf: Don't use tnum_range on array range checking for poke descriptors

Hsin-Wei reported a KASAN splat triggered by their BPF runtime fuzzer which is based on a customized syzkaller:

The problem here is that a range of tnum_range(0, map->max_entries - 1) has limited ability to represent the concrete tight range with the tnum as the set of resulting states from value + mask can result in a superset of the actual intended range, and as such a tnum_in(range, reg->var_off) check may yield true when it shouldn't, for example tnum_range(0, 2) would result in 00XX -> v = 0000, m = 0011 such that the intended set of {0, 1, 2} is here represented by a less precise superset of {0, 1, 2, 3}.

Leer descripción completaMostrar menos

As the register is known const scalar, really just use the concrete reg->var_off.value for the upper index check.

Detalles técnicos trazas, registros y código del informe original

  BUG: KASAN: slab-out-of-bounds in bpf_int_jit_compile+0x1257/0x13f0
  Read of size 8 at addr ffff888004e90b58 by task syz-executor.0/1489
  CPU: 1 PID: 1489 Comm: syz-executor.0 Not tainted 5.19.0 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
  1.13.0-1ubuntu1.1 04/01/2014
  Call Trace:
   <TASK>
   dump_stack_lvl+0x9c/0xc9
   print_address_description.constprop.0+0x1f/0x1f0
   ? bpf_int_jit_compile+0x1257/0x13f0
   kasan_report.cold+0xeb/0x197
   ? kvmalloc_node+0x170/0x200
   ? bpf_int_jit_compile+0x1257/0x13f0
   bpf_int_jit_compile+0x1257/0x13f0
   ? arch_prepare_bpf_dispatcher+0xd0/0xd0
   ? rcu_read_lock_sched_held+0x43/0x70
   bpf_prog_select_runtime+0x3e8/0x640
   ? bpf_obj_name_cpy+0x149/0x1b0
   bpf_prog_load+0x102f/0x2220
   ? __bpf_prog_put.constprop.0+0x220/0x220
   ? find_held_lock+0x2c/0x110
   ? __might_fault+0xd6/0x180
   ? lock_downgrade+0x6e0/0x6e0
   ? lock_is_held_type+0xa6/0x120
   ? __might_fault+0x147/0x180
   __sys_bpf+0x137b/0x6070
   ? bpf_perf_link_attach+0x530/0x530
   ? new_sync_read+0x600/0x600
   ? __fget_files+0x255/0x450
   ? lock_downgrade+0x6e0/0x6e0
   ? fput+0x30/0x1a0
   ? ksys_write+0x1a8/0x260
   __x64_sys_bpf+0x7a/0xc0
   ? syscall_enter_from_user_mode+0x21/0x70
   do_syscall_64+0x3b/0x90
   entry_SYSCALL_64_after_hwframe+0x63/0xcd
  RIP: 0033:0x7f917c4e2c2d

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Puntuación base: 7.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.26%
Percentil entre todas las CVEs puntuadas: 16
Fecha de la puntuación: 5/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1059 Command and Scripting Interpreterexecution75 %
Impacto secundarioT1499.004 Application or System Exploitationimpact60 %

Acceso local (AV:L, PR:L) sin interacción: escalada de privilegios en kernel BPF. KASAN splat evidencia corrupción de memoria que permite ejecución de código o DoS desde contexto local.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Execution Prevention Threat Intelligence Program Restrict Web-Based Content Privileged Account Management Limit Software Installation Filter Network Traffic

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-125

Referencias

JSON original (NVD)

Mostrar

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    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Don't use tnum_range on array range checking for poke descriptors\n\nHsin-Wei reported a KASAN splat triggered by their BPF runtime fuzzer which\nis based on a customized syzkaller:\n\n  BUG: KASAN: slab-out-of-bounds in bpf_int_jit_compile+0x1257/0x13f0\n  Read of size 8 at addr ffff888004e90b58 by task syz-executor.0/1489\n  CPU: 1 PID: 1489 Comm: syz-executor.0 Not tainted 5.19.0 #1\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n  1.13.0-1ubuntu1.1 04/01/2014\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x9c/0xc9\n   print_address_description.constprop.0+0x1f/0x1f0\n   ? bpf_int_jit_compile+0x1257/0x13f0\n   kasan_report.cold+0xeb/0x197\n   ? kvmalloc_node+0x170/0x200\n   ? bpf_int_jit_compile+0x1257/0x13f0\n   bpf_int_jit_compile+0x1257/0x13f0\n   ? arch_prepare_bpf_dispatcher+0xd0/0xd0\n   ? rcu_read_lock_sched_held+0x43/0x70\n   bpf_prog_select_runtime+0x3e8/0x640\n   ? bpf_obj_name_cpy+0x149/0x1b0\n   bpf_prog_load+0x102f/0x2220\n   ? __bpf_prog_put.constprop.0+0x220/0x220\n   ? find_held_lock+0x2c/0x110\n   ? __might_fault+0xd6/0x180\n   ? lock_downgrade+0x6e0/0x6e0\n   ? lock_is_held_type+0xa6/0x120\n   ? __might_fault+0x147/0x180\n   __sys_bpf+0x137b/0x6070\n   ? bpf_perf_link_attach+0x530/0x530\n   ? new_sync_read+0x600/0x600\n   ? __fget_files+0x255/0x450\n   ? lock_downgrade+0x6e0/0x6e0\n   ? fput+0x30/0x1a0\n   ? ksys_write+0x1a8/0x260\n   __x64_sys_bpf+0x7a/0xc0\n   ? syscall_enter_from_user_mode+0x21/0x70\n   do_syscall_64+0x3b/0x90\n   entry_SYSCALL_64_after_hwframe+0x63/0xcd\n  RIP: 0033:0x7f917c4e2c2d\n\nThe problem here is that a range of tnum_range(0, map->max_entries - 1) has\nlimited ability to represent the concrete tight range with the tnum as the\nset of resulting states from value + mask can result in a superset of the\nactual intended range, and as such a tnum_in(range, reg->var_off) check may\nyield true when it shouldn't, for example tnum_range(0, 2) would result in\n00XX -> v = 0000, m = 0011 such that the intended set of {0, 1, 2} is here\nrepresented by a less precise superset of {0, 1, 2, 3}. As the register is\nknown const scalar, really just use the concrete reg->var_off.value for the\nupper index check."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: No use tnum_range en la comprobación del rango de matriz para los descriptores de poke Hsin-Wei informó un splat de KASAN activado por su fuzzer de tiempo de ejecución BPF que se basa en un syzkaller personalizado: ERROR: KASAN: slab-out-of-bounds en bpf_int_jit_compile+0x1257/0x13f0 Lectura de tamaño 8 en la dirección ffff888004e90b58 por la tarea syz-executor.0/1489 CPU: 1 PID: 1489 Comm: syz-executor.0 No contaminado 5.19.0 #1 Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 01/04/2014 Rastreo de llamadas:  dump_stack_lvl+0x9c/0xc9 print_address_description.constprop.0+0x1f/0x1f0 ? bpf_int_jit_compile+0x1257/0x13f0 kasan_report.cold+0xeb/0x197 ? kvmalloc_node+0x170/0x200 ? bpf_int_jit_compile+0x1257/0x13f0 bpf_int_jit_compile+0x1257/0x13f0 ? arch_prepare_bpf_dispatcher+0xd0/0xd0 ? rcu_read_lock_sched_held+0x43/0x70 bpf_prog_select_runtime+0x3e8/0x640 ? bpf_obj_name_cpy+0x149/0x1b0 bpf_prog_load+0x102f/0x2220 ? __bpf_prog_put.constprop.0+0x220/0x220 ? find_held_lock+0x2c/0x110 ? __might_fault+0xd6/0x180 ? lock_downgrade+0x6e0/0x6e0 ? lock_is_held_type+0xa6/0x120 ? __might_fault+0x147/0x180 __sys_bpf+0x137b/0x6070 ? bpf_perf_link_attach+0x530/0x530 ? new_sync_read+0x600/0x600 ? __fget_files+0x255/0x450 ? lock_downgrade+0x6e0/0x6e0 ? fput+0x30/0x1a0 ? ksys_write+0x1a8/0x260 __x64_sys_bpf+0x7a/0xc0 ? syscall_enter_from_user_mode+0x21/0x70 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f917c4e2c2d El problema aquí es que un rango de tnum_range(0, map-&gt;max_entries - 1) tiene una capacidad limitada para representar el rango estrecho concreto con el tnum como el conjunto de estados resultantes de value + mask puede resultar en un superconjunto del rango real deseado, y como tal una comprobación tnum_in(range, reg-&gt;var_off) puede dar como resultado verdadero cuando no debería, por ejemplo tnum_range(0, 2) daría como resultado 00XX -&gt; v = 0000, m = 0011 de modo que el conjunto deseado de {0, 1, 2} está representado aquí por un superconjunto menos preciso de {0, 1, 2, 3}. Como el registro es un escalar constante, simplemente use el valor concreto reg-&gt;var_off.value para la verificación del índice superior."
    }
  ],
  "lastModified": "2026-08-04T10:18:01.983",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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}