CVE-2022-49196

Estado: AnalizadaAlta (7.8)—

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

powerpc/pseries: Fix use after free in remove_phb_dynamic()

In remove_phb_dynamic() we use &phb->io_resource, after we've called device_unregister(&host_bridge->dev). But the unregister may have freed phb, because pcibios_free_controller_deferred() is the release function for the host_bridge.

If there are no outstanding references when we call device_unregister() then phb will be freed out from under us.

This has gone mainly unnoticed, but with slub_debug and page_poison enabled it can lead to a crash:

To avoid it, we can take a reference to the host_bridge->dev until we're done using phb. Then when we drop the reference the phb will be freed.

Detalles técnicos trazas, registros y código del informe original

  PID: 7574   TASK: c0000000d492cb80  CPU: 13  COMMAND: "drmgr"
   #0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc
   #1 [c0000000e4f075d0] oops_end at c000000000029608
   #2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4
   #3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8
   #4 [c0000000e4f076f0] data_access_slb_common_virt at c000000000008b30
   Data SLB Access [380] exception frame:
   R0:  c000000000167250    R1:  c0000000e4f07a00    R2:  c000000002a46100
   R3:  c000000002b39ce8    R4:  00000000000000c0    R5:  00000000000000a9
   R6:  3894674d000000c0    R7:  0000000000000000    R8:  00000000000000ff
   R9:  0000000000000100    R10: 6b6b6b6b6b6b6b6b    R11: 0000000000008000
   R12: c00000000023da80    R13: c0000009ffd38b00    R14: 0000000000000000
   R15: 000000011c87f0f0    R16: 0000000000000006    R17: 0000000000000003
   R18: 0000000000000002    R19: 0000000000000004    R20: 0000000000000005
   R21: 000000011c87ede8    R22: 000000011c87c5a8    R23: 000000011c87d3a0
   R24: 0000000000000000    R25: 0000000000000001    R26: c0000000e4f07cc8
   R27: c00000004d1cc400    R28: c0080000031d00e8    R29: c00000004d23d800
   R30: c00000004d1d2400    R31: c00000004d1d2540
   NIP: c000000000167258    MSR: 8000000000009033    OR3: c000000000e9f474
   CTR: 0000000000000000    LR:  c000000000167250    XER: 0000000020040003
   CCR: 0000000024088420    MQ:  0000000000000000    DAR: 6b6b6b6b6b6b6ba3
   DSISR: c0000000e4f07920     Syscall Result: fffffffffffffff2
   [NIP  : release_resource+56]
   [LR   : release_resource+48]
   #5 [c0000000e4f07a00] release_resource at c000000000167258  (unreliable)
   #6 [c0000000e4f07a30] remove_phb_dynamic at c000000000105648
   #7 [c0000000e4f07ab0] dlpar_remove_slot at c0080000031a09e8 [rpadlpar_io]
   #8 [c0000000e4f07b50] remove_slot_store at c0080000031a0b9c [rpadlpar_io]
   #9 [c0000000e4f07be0] kobj_attr_store at c000000000817d8c
  #10 [c0000000e4f07c00] sysfs_kf_write at c00000000063e504
  #11 [c0000000e4f07c20] kernfs_fop_write_iter at c00000000063d868
  #12 [c0000000e4f07c70] new_sync_write at c00000000054339c
  #13 [c0000000e4f07d10] vfs_write at c000000000546624
  #14 [c0000000e4f07d60] ksys_write at c0000000005469f4
  #15 [c0000000e4f07db0] system_call_exception at c000000000030840
  #16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.27%
Percentil entre todas las CVEs puntuadas: 18
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 principalT1499.004 Application or System Exploitationimpact75 %

Vulnerabilidad de use-after-free (CWE-416) en kernel local con PR:L que causa crash de DoS; acceso local sin interacción del usuario permite elevar impacto mediante corrupción de memoria.

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

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

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      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
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          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/pseries: Fix use after free in remove_phb_dynamic()\n\nIn remove_phb_dynamic() we use &phb->io_resource, after we've called\ndevice_unregister(&host_bridge->dev). But the unregister may have freed\nphb, because pcibios_free_controller_deferred() is the release function\nfor the host_bridge.\n\nIf there are no outstanding references when we call device_unregister()\nthen phb will be freed out from under us.\n\nThis has gone mainly unnoticed, but with slub_debug and page_poison\nenabled it can lead to a crash:\n\n  PID: 7574   TASK: c0000000d492cb80  CPU: 13  COMMAND: \"drmgr\"\n   #0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc\n   #1 [c0000000e4f075d0] oops_end at c000000000029608\n   #2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4\n   #3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8\n   #4 [c0000000e4f076f0] data_access_slb_common_virt at c000000000008b30\n   Data SLB Access [380] exception frame:\n   R0:  c000000000167250    R1:  c0000000e4f07a00    R2:  c000000002a46100\n   R3:  c000000002b39ce8    R4:  00000000000000c0    R5:  00000000000000a9\n   R6:  3894674d000000c0    R7:  0000000000000000    R8:  00000000000000ff\n   R9:  0000000000000100    R10: 6b6b6b6b6b6b6b6b    R11: 0000000000008000\n   R12: c00000000023da80    R13: c0000009ffd38b00    R14: 0000000000000000\n   R15: 000000011c87f0f0    R16: 0000000000000006    R17: 0000000000000003\n   R18: 0000000000000002    R19: 0000000000000004    R20: 0000000000000005\n   R21: 000000011c87ede8    R22: 000000011c87c5a8    R23: 000000011c87d3a0\n   R24: 0000000000000000    R25: 0000000000000001    R26: c0000000e4f07cc8\n   R27: c00000004d1cc400    R28: c0080000031d00e8    R29: c00000004d23d800\n   R30: c00000004d1d2400    R31: c00000004d1d2540\n   NIP: c000000000167258    MSR: 8000000000009033    OR3: c000000000e9f474\n   CTR: 0000000000000000    LR:  c000000000167250    XER: 0000000020040003\n   CCR: 0000000024088420    MQ:  0000000000000000    DAR: 6b6b6b6b6b6b6ba3\n   DSISR: c0000000e4f07920     Syscall Result: fffffffffffffff2\n   [NIP  : release_resource+56]\n   [LR   : release_resource+48]\n   #5 [c0000000e4f07a00] release_resource at c000000000167258  (unreliable)\n   #6 [c0000000e4f07a30] remove_phb_dynamic at c000000000105648\n   #7 [c0000000e4f07ab0] dlpar_remove_slot at c0080000031a09e8 [rpadlpar_io]\n   #8 [c0000000e4f07b50] remove_slot_store at c0080000031a0b9c [rpadlpar_io]\n   #9 [c0000000e4f07be0] kobj_attr_store at c000000000817d8c\n  #10 [c0000000e4f07c00] sysfs_kf_write at c00000000063e504\n  #11 [c0000000e4f07c20] kernfs_fop_write_iter at c00000000063d868\n  #12 [c0000000e4f07c70] new_sync_write at c00000000054339c\n  #13 [c0000000e4f07d10] vfs_write at c000000000546624\n  #14 [c0000000e4f07d60] ksys_write at c0000000005469f4\n  #15 [c0000000e4f07db0] system_call_exception at c000000000030840\n  #16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168\n\nTo avoid it, we can take a reference to the host_bridge->dev until we're\ndone using phb. Then when we drop the reference the phb will be freed."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: powerpc/pseries: Se corrige el uso después de liberar en remove_phb_dynamic() En remove_phb_dynamic() usamos &amp;phb-&gt;io_resource, después de haber llamado a device_unregister(&amp;host_bridge-&gt;dev). Pero la anulación del registro puede haber liberado a phb, porque pcibios_free_controller_deferred() es la función de liberación para host_bridge. Si no hay referencias pendientes cuando llamamos a device_unregister(), phb se liberará de nosotros. Esto ha pasado desapercibido, pero con slub_debug y page_poison habilitados puede provocar un bloqueo: PID: 7574 TAREA: c0000000d492cb80 CPU: 13 COMANDO: \"drmgr\" #0 [c0000000e4f075a0] crash_kexec at c00000000027d7dc #1 [c0000000e4f075d0] oops_end at c000000000029608 #2 [c0000000e4f07650] __bad_page_fault at c0000000000904b4 #3 [c0000000e4f076c0] do_bad_slb_fault at c00000000009a5a8 #4 [c0000000e4f076f0] data_access_slb_common_virt en c000000000008b30 Marco de excepción de acceso a datos SLB [380]: R0: c000000000167250 R1: c0000000e4f07a00 R2: c000000002a46100 R3: c000000002b39ce8 R4: 00000000000000c0 R5: 00000000000000a9 R6: 3894674d000000c0 R7: 0000000000000000 R8: 000000000000000ff R9: 0000000000000100 R10: 6b6b6b6b6b6b6b6b R11: 0000000000008000 R12: c00000000023da80 R13: c0000009ffd38b00 R14: 0000000000000000 R15: 000000011c87f0f0 R16: 0000000000000006 R17: 0000000000000003 R18: 0000000000000002 R19: 0000000000000004 R20: 0000000000000005 R21: 000000011c87ede8 R22: 000000011c87c5a8 R23: 000000011c87d3a0 R24: 0000000000000000 R25: 0000000000000001 R26: c0000000e4f07cc8 R27: c00000004d1cc400 R28: c0080000031d00e8 R29: c00000004d23d800 R30: c00000004d1d2400 R31: c00000004d1d2540 PIP: c000000000167258 MSR: 8000000000009033 OR3: c000000000e9f474 CTR: 0000000000000000 LR: c000000000167250 XER: 0000000020040003 CCR: 0000000024088420 MQ: 0000000000000000 DAR: 6b6b6b6b6b6b6ba3 DSISR: c0000000e4f07920 Resultado de llamada al sistema: fffffffffffffff2 [NIP: release_resource+56] [LR: release_resource+48] #5 [c0000000e4f07a00] release_resource en c000000000167258 (no confiable) #6 [c0000000e4f07a30] remove_phb_dynamic en c000000000105648 #7 [c0000000e4f07ab0] dlpar_remove_slot en c0080000031a09e8 [rpadlpar_io] #8 [c0000000e4f07b50] remove_slot_store en c0080000031a0b9c [rpadlpar_io] #9 [c0000000e4f07be0] kobj_attr_store en c000000000817d8c #10 [c0000000e4f07c00] sysfs_kf_write en c00000000063e504 #11 [c0000000e4f07c20] kernfs_fop_write_iter en c00000000063d868 #12 [c0000000e4f07c70] new_sync_write en c00000000054339c #13 [c0000000e4f07d10] vfs_write en c000000000546624 #14 [c0000000e4f07d60] ksys_write en c0000000005469f4 #15 [c0000000e4f07db0] system_call_exception at c000000000030840 #16 [c0000000e4f07e10] system_call_vectored_common at c00000000000c168 Para evitarlo, podemos tomar una referencia a host_bridge-&gt;dev hasta que terminemos de usar phb. Luego, cuando eliminemos la referencia, se liberará phb."
    }
  ],
  "lastModified": "2026-06-17T05:17:21.210",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "BA789D31-0F96-422B-81E8-27E5D87B93D0",
              "versionEndExcluding": "3.17",
              "versionStartIncluding": "3.16.39"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "9CC2B4A2-19D0-4A85-94C5-B8A6D1F0DA6A",
              "versionEndExcluding": "5.15.33",
              "versionStartIncluding": "4.7.8"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "20C43679-0439-405A-B97F-685BEE50613B",
              "versionEndExcluding": "5.16.19",
              "versionStartIncluding": "5.16"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "210C679C-CF84-44A3-8939-E629C87E54BF",
              "versionEndExcluding": "5.17.2",
              "versionStartIncluding": "5.17"
            }
          ],
          "operator": "OR"
        }
      ]
    }
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}