CVE-2022-50256

Estado: AnalizadaAlta (7.8)—

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

drm/meson: remove drm bridges at aggregate driver unbind time

drm bridges added by meson_encoder_hdmi_init and meson_encoder_cvbs_init were not manually removed at module unload time, which caused dangling references to freed memory to remain linked in the global bridge_list.

When loading the driver modules back in, the same functions would again call drm_bridge_add, and when traversing the global bridge_list, would end up peeking into freed memory.

Once again KASAN revealed the problem:

[ +0.000095] ============================================================= [ +0.000008] BUG: KASAN: use-after-free in __list_add_valid+0x9c/0x120 [ +0.000018] Read of size 8 at addr ffff00003da291f0 by task modprobe/2483

Detalles técnicos trazas, registros y código del informe original

[  +0.000018] CPU: 3 PID: 2483 Comm: modprobe Tainted: G         C O      5.19.0-rc6-lrmbkasan+ #1
[  +0.000011] Hardware name: Hardkernel ODROID-N2Plus (DT)
[  +0.000008] Call trace:
[  +0.000006]  dump_backtrace+0x1ec/0x280
[  +0.000012]  show_stack+0x24/0x80
[  +0.000008]  dump_stack_lvl+0x98/0xd4
[  +0.000011]  print_address_description.constprop.0+0x80/0x520
[  +0.000011]  print_report+0x128/0x260
[  +0.000008]  kasan_report+0xb8/0xfc
[  +0.000008]  __asan_report_load8_noabort+0x3c/0x50
[  +0.000009]  __list_add_valid+0x9c/0x120
[  +0.000009]  drm_bridge_add+0x6c/0x104 [drm]
[  +0.000165]  dw_hdmi_probe+0x1900/0x2360 [dw_hdmi]
[  +0.000022]  meson_dw_hdmi_bind+0x520/0x814 [meson_dw_hdmi]
[  +0.000014]  component_bind+0x174/0x520
[  +0.000012]  component_bind_all+0x1a8/0x38c
[  +0.000010]  meson_drv_bind_master+0x5e8/0xb74 [meson_drm]
[  +0.000032]  meson_drv_bind+0x20/0x2c [meson_drm]
[  +0.000027]  try_to_bring_up_aggregate_device+0x19c/0x390
[  +0.000010]  component_master_add_with_match+0x1c8/0x284
[  +0.000009]  meson_drv_probe+0x274/0x280 [meson_drm]
[  +0.000026]  platform_probe+0xd0/0x220
[  +0.000009]  really_probe+0x3ac/0xa80
[  +0.000009]  __driver_probe_device+0x1f8/0x400
[  +0.000009]  driver_probe_device+0x68/0x1b0
[  +0.000009]  __driver_attach+0x20c/0x480
[  +0.000008]  bus_for_each_dev+0x114/0x1b0
[  +0.000009]  driver_attach+0x48/0x64
[  +0.000008]  bus_add_driver+0x390/0x564
[  +0.000009]  driver_register+0x1a8/0x3e4
[  +0.000009]  __platform_driver_register+0x6c/0x94
[  +0.000008]  meson_drm_platform_driver_init+0x3c/0x1000 [meson_drm]
[  +0.000027]  do_one_initcall+0xc4/0x2b0
[  +0.000011]  do_init_module+0x154/0x570
[  +0.000011]  load_module+0x1a78/0x1ea4
[  +0.000008]  __do_sys_init_module+0x184/0x1cc
[  +0.000009]  __arm64_sys_init_module+0x78/0xb0
[  +0.000009]  invoke_syscall+0x74/0x260
[  +0.000009]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000012]  el0t_64_sync_handler+0x11c/0x150
[  +0.000008]  el0t_64_sync+0x18c/0x190

[  +0.000016] Allocated by task 879:
[  +0.000008]  kasan_save_stack+0x2c/0x5c
[  +0.000011]  __kasan_kmalloc+0x90/0xd0
[  +0.000007]  __kmalloc+0x278/0x4a0
[  +0.000011]  mpi_resize+0x13c/0x1d0
[  +0.000011]  mpi_powm+0xd24/0x1570
[  +0.000009]  rsa_enc+0x1a4/0x30c
[  +0.000009]  pkcs1pad_verify+0x3f0/0x580
[  +0.000009]  public_key_verify_signature+0x7a8/0xba4
[  +0.000010]  public_key_verify_signature_2+0x40/0x60
[  +0.000008]  verify_signature+0xb4/0x114
[  +0.000008]  pkcs7_validate_trust_one.constprop.0+0x3b8/0x574
[  +0.000009]  pkcs7_validate_trust+0xb8/0x15c
[  +0.000008]  verify_pkcs7_message_sig+0xec/0x1b0
[  +0.000012]  verify_pkcs7_signature+0x78/0xac
[  +0.000007]  mod_verify_sig+0x110/0x190
[  +0.000009]  module_sig_check+0x114/0x1e0
[  +0.000009]  load_module+0xa0/0x1ea4
[  +0.000008]  __do_sys_init_module+0x184/0x1cc
[  +0.000008]  __arm64_sys_init_module+0x78/0xb0
[  +0.000008]  invoke_syscall+0x74/0x260
[  +0.000009]  el0_svc_common.constprop.0+0x1a8/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000009]  el0t_64_sync_handler+0x11c/0x150
[  +0.000009]  el0t_64
---truncated---

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: 0.16%
Percentil entre todas las CVEs puntuadas: 5
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 escalation75 %
Impacto principalT1059 Command and Scripting Interpreterexecution60 %

CWE-416 (use-after-free) con acceso local (AV:L) y privilegios limitados (PR:L) permite escalada de privilegios; ejecución de código implícita en la manipulación de memoria del kernel.

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 Behavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2022-50256",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "e67f6037ae1be34b2b686bab72caa41d57714534",
              "lessThan": "de2b6ebe0cb7746b5b6b35d79e150d934392b958",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e67f6037ae1be34b2b686bab72caa41d57714534",
              "lessThan": "fc1fd114dde3d2623ac37676df3d74ffeedb0da8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e67f6037ae1be34b2b686bab72caa41d57714534",
              "lessThan": "09847723c12fc2753749cec3939a02ee92dac468",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1c5439a716122cd86530d261cd1bf7ba43b3cdd8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "7e88f6d40f5875212f9d9ee8ba19147159908d4a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "5.15.33",
              "lessThan": "5.16",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "5.16.19",
              "lessThan": "5.17",
              "versionType": "semver"
            }
          ],
          "programFiles": [
            "drivers/gpu/drm/meson/meson_drv.c",
            "drivers/gpu/drm/meson/meson_drv.h",
            "drivers/gpu/drm/meson/meson_encoder_cvbs.c",
            "drivers/gpu/drm/meson/meson_encoder_cvbs.h",
            "drivers/gpu/drm/meson/meson_encoder_hdmi.c",
            "drivers/gpu/drm/meson/meson_encoder_hdmi.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.17",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.19.17",
              "versionType": "semver",
              "lessThanOrEqual": "5.19.*"
            },
            {
              "status": "unaffected",
              "version": "6.0.3",
              "versionType": "semver",
              "lessThanOrEqual": "6.0.*"
            },
            {
              "status": "unaffected",
              "version": "6.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/gpu/drm/meson/meson_drv.c",
            "drivers/gpu/drm/meson/meson_drv.h",
            "drivers/gpu/drm/meson/meson_encoder_cvbs.c",
            "drivers/gpu/drm/meson/meson_encoder_cvbs.h",
            "drivers/gpu/drm/meson/meson_encoder_hdmi.c",
            "drivers/gpu/drm/meson/meson_encoder_hdmi.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-09-15T14:15:36.363",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/09847723c12fc2753749cec3939a02ee92dac468",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/de2b6ebe0cb7746b5b6b35d79e150d934392b958",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fc1fd114dde3d2623ac37676df3d74ffeedb0da8",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/meson: remove drm bridges at aggregate driver unbind time\n\ndrm bridges added by meson_encoder_hdmi_init and meson_encoder_cvbs_init\nwere not manually removed at module unload time, which caused dangling\nreferences to freed memory to remain linked in the global bridge_list.\n\nWhen loading the driver modules back in, the same functions would again\ncall drm_bridge_add, and when traversing the global bridge_list, would\nend up peeking into freed memory.\n\nOnce again KASAN revealed the problem:\n\n[  +0.000095] =============================================================\n[  +0.000008] BUG: KASAN: use-after-free in __list_add_valid+0x9c/0x120\n[  +0.000018] Read of size 8 at addr ffff00003da291f0 by task modprobe/2483\n\n[  +0.000018] CPU: 3 PID: 2483 Comm: modprobe Tainted: G         C O      5.19.0-rc6-lrmbkasan+ #1\n[  +0.000011] Hardware name: Hardkernel ODROID-N2Plus (DT)\n[  +0.000008] Call trace:\n[  +0.000006]  dump_backtrace+0x1ec/0x280\n[  +0.000012]  show_stack+0x24/0x80\n[  +0.000008]  dump_stack_lvl+0x98/0xd4\n[  +0.000011]  print_address_description.constprop.0+0x80/0x520\n[  +0.000011]  print_report+0x128/0x260\n[  +0.000008]  kasan_report+0xb8/0xfc\n[  +0.000008]  __asan_report_load8_noabort+0x3c/0x50\n[  +0.000009]  __list_add_valid+0x9c/0x120\n[  +0.000009]  drm_bridge_add+0x6c/0x104 [drm]\n[  +0.000165]  dw_hdmi_probe+0x1900/0x2360 [dw_hdmi]\n[  +0.000022]  meson_dw_hdmi_bind+0x520/0x814 [meson_dw_hdmi]\n[  +0.000014]  component_bind+0x174/0x520\n[  +0.000012]  component_bind_all+0x1a8/0x38c\n[  +0.000010]  meson_drv_bind_master+0x5e8/0xb74 [meson_drm]\n[  +0.000032]  meson_drv_bind+0x20/0x2c [meson_drm]\n[  +0.000027]  try_to_bring_up_aggregate_device+0x19c/0x390\n[  +0.000010]  component_master_add_with_match+0x1c8/0x284\n[  +0.000009]  meson_drv_probe+0x274/0x280 [meson_drm]\n[  +0.000026]  platform_probe+0xd0/0x220\n[  +0.000009]  really_probe+0x3ac/0xa80\n[  +0.000009]  __driver_probe_device+0x1f8/0x400\n[  +0.000009]  driver_probe_device+0x68/0x1b0\n[  +0.000009]  __driver_attach+0x20c/0x480\n[  +0.000008]  bus_for_each_dev+0x114/0x1b0\n[  +0.000009]  driver_attach+0x48/0x64\n[  +0.000008]  bus_add_driver+0x390/0x564\n[  +0.000009]  driver_register+0x1a8/0x3e4\n[  +0.000009]  __platform_driver_register+0x6c/0x94\n[  +0.000008]  meson_drm_platform_driver_init+0x3c/0x1000 [meson_drm]\n[  +0.000027]  do_one_initcall+0xc4/0x2b0\n[  +0.000011]  do_init_module+0x154/0x570\n[  +0.000011]  load_module+0x1a78/0x1ea4\n[  +0.000008]  __do_sys_init_module+0x184/0x1cc\n[  +0.000009]  __arm64_sys_init_module+0x78/0xb0\n[  +0.000009]  invoke_syscall+0x74/0x260\n[  +0.000009]  el0_svc_common.constprop.0+0xcc/0x260\n[  +0.000008]  do_el0_svc+0x50/0x70\n[  +0.000007]  el0_svc+0x68/0x1a0\n[  +0.000012]  el0t_64_sync_handler+0x11c/0x150\n[  +0.000008]  el0t_64_sync+0x18c/0x190\n\n[  +0.000016] Allocated by task 879:\n[  +0.000008]  kasan_save_stack+0x2c/0x5c\n[  +0.000011]  __kasan_kmalloc+0x90/0xd0\n[  +0.000007]  __kmalloc+0x278/0x4a0\n[  +0.000011]  mpi_resize+0x13c/0x1d0\n[  +0.000011]  mpi_powm+0xd24/0x1570\n[  +0.000009]  rsa_enc+0x1a4/0x30c\n[  +0.000009]  pkcs1pad_verify+0x3f0/0x580\n[  +0.000009]  public_key_verify_signature+0x7a8/0xba4\n[  +0.000010]  public_key_verify_signature_2+0x40/0x60\n[  +0.000008]  verify_signature+0xb4/0x114\n[  +0.000008]  pkcs7_validate_trust_one.constprop.0+0x3b8/0x574\n[  +0.000009]  pkcs7_validate_trust+0xb8/0x15c\n[  +0.000008]  verify_pkcs7_message_sig+0xec/0x1b0\n[  +0.000012]  verify_pkcs7_signature+0x78/0xac\n[  +0.000007]  mod_verify_sig+0x110/0x190\n[  +0.000009]  module_sig_check+0x114/0x1e0\n[  +0.000009]  load_module+0xa0/0x1ea4\n[  +0.000008]  __do_sys_init_module+0x184/0x1cc\n[  +0.000008]  __arm64_sys_init_module+0x78/0xb0\n[  +0.000008]  invoke_syscall+0x74/0x260\n[  +0.000009]  el0_svc_common.constprop.0+0x1a8/0x260\n[  +0.000008]  do_el0_svc+0x50/0x70\n[  +0.000007]  el0_svc+0x68/0x1a0\n[  +0.000009]  el0t_64_sync_handler+0x11c/0x150\n[  +0.000009]  el0t_64\n---truncated---"
    }
  ],
  "lastModified": "2026-08-15T13:17:31.143",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6D9E41A0-73E6-47EF-B833-DBA6045CECFB",
              "versionEndExcluding": "5.19.17",
              "versionStartIncluding": "4.10"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "5BCD8201-B847-4442-B894-70D430128DEF",
              "versionEndExcluding": "6.0.3",
              "versionStartIncluding": "6.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}