CVE-2022-49257

Estado: AnalizadaMedia (5.5)—

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

watch_queue: Fix NULL dereference in error cleanup

In watch_queue_set_size(), the error cleanup code doesn't take account of the fact that __free_page() can't handle a NULL pointer when trying to free up buffer pages that did get allocated.

Fix this by only calling __free_page() on the pages actually allocated.

Without the fix, this can lead to something like the following:

Detalles técnicos trazas, registros y código del informe original

BUG: KASAN: null-ptr-deref in __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473
Read of size 4 at addr 0000000000000034 by task syz-executor168/3599
...
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 __kasan_report mm/kasan/report.c:446 [inline]
 kasan_report.cold+0x66/0xdf mm/kasan/report.c:459
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 page_ref_count include/linux/page_ref.h:67 [inline]
 put_page_testzero include/linux/mm.h:717 [inline]
 __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473
 watch_queue_set_size+0x499/0x630 kernel/watch_queue.c:275
 pipe_ioctl+0xac/0x2b0 fs/pipe.c:632
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 5.5

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).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-476

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2022-49257",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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          "programFiles": [
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          "defaultStatus": "affected"
        }
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  "published": "2025-02-26T07:01:02.597",
  "references": [
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      "tags": [
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  "weaknesses": [
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      "source": "nvd@nist.gov",
      "description": [
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          "value": "CWE-476"
        }
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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwatch_queue: Fix NULL dereference in error cleanup\n\nIn watch_queue_set_size(), the error cleanup code doesn't take account of\nthe fact that __free_page() can't handle a NULL pointer when trying to free\nup buffer pages that did get allocated.\n\nFix this by only calling __free_page() on the pages actually allocated.\n\nWithout the fix, this can lead to something like the following:\n\nBUG: KASAN: null-ptr-deref in __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473\nRead of size 4 at addr 0000000000000034 by task syz-executor168/3599\n...\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\n __kasan_report mm/kasan/report.c:446 [inline]\n kasan_report.cold+0x66/0xdf mm/kasan/report.c:459\n check_region_inline mm/kasan/generic.c:183 [inline]\n kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189\n instrument_atomic_read include/linux/instrumented.h:71 [inline]\n atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]\n page_ref_count include/linux/page_ref.h:67 [inline]\n put_page_testzero include/linux/mm.h:717 [inline]\n __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473\n watch_queue_set_size+0x499/0x630 kernel/watch_queue.c:275\n pipe_ioctl+0xac/0x2b0 fs/pipe.c:632\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:874 [inline]\n __se_sys_ioctl fs/ioctl.c:860 [inline]\n __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: watch_queue: Se corrige la desreferencia NULL en la limpieza de errores En watch_queue_set_size(), el código de limpieza de errores no tiene en cuenta el hecho de que __free_page() no puede manejar un puntero NULL al intentar liberar páginas de búfer que sí se asignaron. Solucione esto llamando a __free_page() solo en las páginas realmente asignadas. Sin la corrección, esto puede llevar a algo como lo siguiente: ERROR: KASAN: null-ptr-deref en __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473 Lectura de tamaño 4 en la dirección 0000000000000034 por la tarea syz-executor168/3599 ... Seguimiento de llamadas:  __dump_stack lib/dump_stack.c:88 [en línea] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 __kasan_report mm/kasan/report.c:446 [en línea] kasan_report.cold+0x66/0xdf mm/kasan/report.c:459 check_region_inline mm/kasan/generic.c:183 [en línea] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 instrument_atomic_read include/linux/instrumented.h:71 [en línea] atomic_read include/linux/atomic/atomic-instrumented.h:27 [en línea] page_ref_count include/linux/page_ref.h:67 [en línea] put_page_testzero include/linux/mm.h:717 [en línea] __free_pages+0x1f/0x1b0 mm/page_alloc.c:5473 watch_queue_set_size+0x499/0x630 kernel/watch_queue.c:275 pipe_ioctl+0xac/0x2b0 fs/pipe.c:632 vfs_ioctl fs/ioctl.c:51 [en línea] __do_sys_ioctl fs/ioctl.c:874 [en línea] __se_sys_ioctl fs/ioctl.c:860 [en línea] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [en línea] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae"
    }
  ],
  "lastModified": "2026-06-17T05:17:31.643",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}