FKIE_CVE-2026-23467

Vulnerability from fkie_nvd - Published: 2026-04-03 16:16 - Updated: 2026-11-05 22:18
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/i915/dmc: Fix an unlikely NULL pointer deference at probe intel_dmc_update_dc6_allowed_count() oopses when DMC hasn't been initialized, and dmc is thus NULL. That would be the case when the call path is intel_power_domains_init_hw() -> {skl,bxt,icl}_display_core_init() -> gen9_set_dc_state() -> intel_dmc_update_dc6_allowed_count(), as intel_power_domains_init_hw() is called *before* intel_dmc_init(). However, gen9_set_dc_state() calls intel_dmc_update_dc6_allowed_count() conditionally, depending on the current and target DC states. At probe, the target is disabled, but if DC6 is enabled, the function is called, and an oops follows. Apparently it's quite unlikely that DC6 is enabled at probe, as we haven't seen this failure mode before. It is also strange to have DC6 enabled at boot, since that would require the DMC firmware (loaded by BIOS); the BIOS loading the DMC firmware and the driver stopping / reprogramming the firmware is a poorly specified sequence and as such unlikely an intentional BIOS behaviour. It's more likely that BIOS is leaving an unintentionally enabled DC6 HW state behind (without actually loading the required DMC firmware for this). The tracking of the DC6 allowed counter only works if starting / stopping the counter depends on the _SW_ DC6 state vs. the current _HW_ DC6 state (since stopping the counter requires the DC5 counter captured when the counter was started). Thus, using the HW DC6 state is incorrect and it also leads to the above oops. Fix both issues by using the SW DC6 state for the tracking. This is v2 of the fix originally sent by Jani, updated based on the first Link: discussion below. (cherry picked from commit 2344b93af8eb5da5d496b4e0529d35f0f559eaf0)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0b35d11fbbcfd1079c8489282a341944228835e3Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/631317825d44283abfe7a8374f13a76ce2032bb8Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ac57eb3b7d2ad649025b5a0fa207315f755ac4f6Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/i915/display/intel_display_power_well.c",
            "drivers/gpu/drm/i915/display/intel_dmc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0b35d11fbbcfd1079c8489282a341944228835e3",
              "status": "affected",
              "version": "88c1f9a4d36de61f87cc52aac670020b13d1ccaa",
              "versionType": "git"
            },
            {
              "lessThan": "631317825d44283abfe7a8374f13a76ce2032bb8",
              "status": "affected",
              "version": "88c1f9a4d36de61f87cc52aac670020b13d1ccaa",
              "versionType": "git"
            },
            {
              "lessThan": "ac57eb3b7d2ad649025b5a0fa207315f755ac4f6",
              "status": "affected",
              "version": "88c1f9a4d36de61f87cc52aac670020b13d1ccaa",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/i915/display/intel_display_power_well.c",
            "drivers/gpu/drm/i915/display/intel_dmc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.20",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "1C570CE1-BC61-4BE6-9393-FD0CA8637367",
              "versionEndExcluding": "6.18.20",
              "versionStartIncluding": "6.16",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "96D34333-38BE-4414-9E79-6EB764329581",
              "versionEndExcluding": "6.19.10",
              "versionStartIncluding": "6.19",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
              "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
              "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
              "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2",
              "vulnerable": true
            }
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          "negate": false,
          "operator": "OR"
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/i915/dmc: Fix an unlikely NULL pointer deference at probe\n\nintel_dmc_update_dc6_allowed_count() oopses when DMC hasn\u0027t been\ninitialized, and dmc is thus NULL.\n\nThat would be the case when the call path is\nintel_power_domains_init_hw() -\u003e {skl,bxt,icl}_display_core_init() -\u003e\ngen9_set_dc_state() -\u003e intel_dmc_update_dc6_allowed_count(), as\nintel_power_domains_init_hw() is called *before* intel_dmc_init().\n\nHowever, gen9_set_dc_state() calls intel_dmc_update_dc6_allowed_count()\nconditionally, depending on the current and target DC states. At probe,\nthe target is disabled, but if DC6 is enabled, the function is called,\nand an oops follows. Apparently it\u0027s quite unlikely that DC6 is enabled\nat probe, as we haven\u0027t seen this failure mode before.\n\nIt is also strange to have DC6 enabled at boot, since that would require\nthe DMC firmware (loaded by BIOS); the BIOS loading the DMC firmware and\nthe driver stopping / reprogramming the firmware is a poorly specified\nsequence and as such unlikely an intentional BIOS behaviour. It\u0027s more\nlikely that BIOS is leaving an unintentionally enabled DC6 HW state\nbehind (without actually loading the required DMC firmware for this).\n\nThe tracking of the DC6 allowed counter only works if starting /\nstopping the counter depends on the _SW_ DC6 state vs. the current _HW_\nDC6 state (since stopping the counter requires the DC5 counter captured\nwhen the counter was started). Thus, using the HW DC6 state is incorrect\nand it also leads to the above oops. Fix both issues by using the SW DC6\nstate for the tracking.\n\nThis is v2 of the fix originally sent by Jani, updated based on the\nfirst Link: discussion below.\n\n(cherry picked from commit 2344b93af8eb5da5d496b4e0529d35f0f559eaf0)"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ndrm/i915/dmc: Corrige una desreferencia de puntero NULL poco probable durante la sonda\n\nintel_dmc_update_dc6_allowed_count() falla (oops) cuando DMC no ha sido inicializado, y dmc es por lo tanto NULL.\n\nEse ser\u00eda el caso cuando la ruta de llamada es intel_power_domains_init_hw()  -\u003e  {skl,bxt,icl}_display_core_init()  -\u003e  gen9_set_dc_state()  -\u003e  intel_dmc_update_dc6_allowed_count(), ya que intel_power_domains_init_hw() es llamado antes de intel_dmc_init().\n\nSin embargo, gen9_set_dc_state() llama a intel_dmc_update_dc6_allowed_count() condicionalmente, dependiendo de los estados DC actual y objetivo. Durante la sonda, el objetivo est\u00e1 deshabilitado, pero si DC6 est\u00e1 habilitado, la funci\u00f3n es llamada, y un oops ocurre. Aparentemente es bastante improbable que DC6 est\u00e9 habilitado durante la sonda, ya que no hemos visto este modo de fallo antes.\n\nTambi\u00e9n es extra\u00f1o tener DC6 habilitado durante el arranque, ya que eso requerir\u00eda el firmware DMC (cargado por la BIOS); la carga del firmware DMC por parte de la BIOS y el controlador deteniendo / reprogramando el firmware es una secuencia mal especificada y, como tal, es poco probable que sea un comportamiento intencional de la BIOS. Es m\u00e1s probable que la BIOS est\u00e9 dejando un estado HW DC6 habilitado de forma no intencional (sin cargar realmente el firmware DMC requerido para esto).\n\nEl seguimiento del contador permitido de DC6 solo funciona si el inicio / detenci\u00f3n del contador depende del estado DC6 _SW_ frente al estado DC6 _HW_ actual (ya que detener el contador requiere el contador DC5 capturado cuando se inici\u00f3 el contador). Por lo tanto, usar el estado HW DC6 es incorrecto y tambi\u00e9n conduce al oops mencionado. Corrige ambos problemas usando el estado SW DC6 para el seguimiento.\n\nEsta es la v2 de la correcci\u00f3n enviada originalmente por Jani, actualizada bas\u00e1ndose en la primera discusi\u00f3n de Enlace: a continuaci\u00f3n.\n\n(seleccionado de la revisi\u00f3n 2344b93af8eb5da5d496b4e0529d35f0f559eaf0)"
    }
  ],
  "id": "CVE-2026-23467",
  "lastModified": "2026-11-05T22:18:27.427",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-23467",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-11-05T21:31:34.178240Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-04-03T16:16:34.177",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/0b35d11fbbcfd1079c8489282a341944228835e3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/631317825d44283abfe7a8374f13a76ce2032bb8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ac57eb3b7d2ad649025b5a0fa207315f755ac4f6"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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