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CVE-2025-22031

Estado: ModificadaMedia (5.5)—

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

PCI/bwctrl: Fix NULL pointer dereference on bus number exhaustion

When BIOS neglects to assign bus numbers to PCI bridges, the kernel attempts to correct that during PCI device enumeration. If it runs out of bus numbers, no pci_bus is allocated and the "subordinate" pointer in the bridge's pci_dev remains NULL.

The PCIe bandwidth controller erroneously does not check for a NULL subordinate pointer and dereferences it on probe.

Bandwidth control of unusable devices below the bridge is of questionable utility, so simply error out instead. This mirrors what PCIe hotplug does since commit 62e4492c3063 ("PCI: Prevent NULL dereference during pciehp probe").

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The PCI core emits a message with KERN_INFO severity if it has run out of bus numbers. PCIe hotplug emits an additional message with KERN_ERR severity to inform the user that hotplug functionality is disabled at the bridge. A similar message for bandwidth control does not seem merited, given that its only purpose so far is to expose an up-to-date link speed in sysfs and throttle the link speed on certain laptops with limited Thermal Design Power. So error out silently.

User-visible messages:

Detalles técnicos trazas, registros y código del informe original
  pci 0000:16:02.0: bridge configuration invalid ([bus 00-00]), reconfiguring
  [...]
  pci_bus 0000:45: busn_res: [bus 45-74] end is updated to 74
  pci 0000:16:02.0: devices behind bridge are unusable because [bus 45-74] cannot be assigned for them
  [...]
  pcieport 0000:16:02.0: pciehp: Hotplug bridge without secondary bus, ignoring
  [...]
  BUG: kernel NULL pointer dereference
  RIP: pcie_update_link_speed
  pcie_bwnotif_enable
  pcie_bwnotif_probe
  pcie_port_probe_service
  really_probe

CVSS

Probabilidad de explotación (EPSS)

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

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2025-22031",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-22031",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2025-10-01T17:05:12.952286Z"
        }
      }
    ],
    "cvssMetricV31": [
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        "source": "nvd@nist.gov",
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          "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
      },
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        "cvssData": {
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          "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"
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        "impactScore": 3.6,
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          ],
          "programFiles": [
            "drivers/pci/pcie/bwctrl.c"
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          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          "versions": [
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            },
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              "status": "unaffected",
              "version": "0",
              "lessThan": "6.13",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.13.11",
              "versionType": "semver",
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              "status": "unaffected",
              "version": "6.14.2",
              "versionType": "semver",
              "lessThanOrEqual": "6.14.*"
            },
            {
              "status": "unaffected",
              "version": "6.15",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/pci/pcie/bwctrl.c"
          ],
          "defaultStatus": "affected"
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  ],
  "published": "2025-04-16T15:15:55.710",
  "references": [
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      "tags": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
      "url": "https://git.kernel.org/stable/c/667f053b05f00a007738cd7ed6fa1901de19dc7e",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "tags": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
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    },
    {
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      "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\nPCI/bwctrl: Fix NULL pointer dereference on bus number exhaustion\n\nWhen BIOS neglects to assign bus numbers to PCI bridges, the kernel\nattempts to correct that during PCI device enumeration.  If it runs out\nof bus numbers, no pci_bus is allocated and the \"subordinate\" pointer in\nthe bridge's pci_dev remains NULL.\n\nThe PCIe bandwidth controller erroneously does not check for a NULL\nsubordinate pointer and dereferences it on probe.\n\nBandwidth control of unusable devices below the bridge is of questionable\nutility, so simply error out instead.  This mirrors what PCIe hotplug does\nsince commit 62e4492c3063 (\"PCI: Prevent NULL dereference during pciehp\nprobe\").\n\nThe PCI core emits a message with KERN_INFO severity if it has run out of\nbus numbers.  PCIe hotplug emits an additional message with KERN_ERR\nseverity to inform the user that hotplug functionality is disabled at the\nbridge.  A similar message for bandwidth control does not seem merited,\ngiven that its only purpose so far is to expose an up-to-date link speed\nin sysfs and throttle the link speed on certain laptops with limited\nThermal Design Power.  So error out silently.\n\nUser-visible messages:\n\n  pci 0000:16:02.0: bridge configuration invalid ([bus 00-00]), reconfiguring\n  [...]\n  pci_bus 0000:45: busn_res: [bus 45-74] end is updated to 74\n  pci 0000:16:02.0: devices behind bridge are unusable because [bus 45-74] cannot be assigned for them\n  [...]\n  pcieport 0000:16:02.0: pciehp: Hotplug bridge without secondary bus, ignoring\n  [...]\n  BUG: kernel NULL pointer dereference\n  RIP: pcie_update_link_speed\n  pcie_bwnotif_enable\n  pcie_bwnotif_probe\n  pcie_port_probe_service\n  really_probe"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: PCI/bwctrl: Corrección de la desreferencia de puntero nulo al agotar el número de bus. Cuando la BIOS no asigna números de bus a los puentes PCI, el kernel intenta corregirlo durante la enumeración de dispositivos PCI. Si se agotan los números de bus, no se asigna ningún pci_bus y el puntero \"subordinado\" en el pci_dev del puente permanece nulo. El controlador de ancho de banda PCIe no busca erróneamente un puntero subordinado nulo y lo desreferencia al sondear. El control del ancho de banda de los dispositivos inutilizables debajo del puente es de dudosa utilidad, por lo que simplemente se genera un error. Esto refleja lo que hace PCIe hotplug desde el commit 62e4492c3063 (\"PCI: Evitar la desreferencia de puntero nulo durante el sondeo pciehp\"). El núcleo PCI emite un mensaje con severidad KERN_INFO si se agotan los números de bus. PCIe hotplug emite un mensaje adicional con severidad KERN_ERR para informar al usuario que la función hotplug está deshabilitada en el puente. Un mensaje similar para el control del ancho de banda no parece justificado, dado que su único propósito hasta ahora es mostrar una velocidad de enlace actualizada en sysfs y limitarla en ciertas computadoras portátiles con potencia de diseño térmico limitada. Por lo tanto, el error se emite silenciosamente. Mensajes visibles para el usuario: pci 0000:16:02.0: configuración de puente no válida ([bus 00-00]), reconfigurando [...] pci_bus 0000:45: busn_res: el extremo [bus 45-74] se actualiza a 74 pci 0000:16:02.0: los dispositivos detrás del puente no se pueden usar porque no se puede asignar [bus 45-74] para ellos [...] pcieport 0000:16:02.0: pciehp: Puente hot-plug sin bus secundario, ignorando [...] ERROR: desreferencia de puntero NULL del kernel RIP: pcie_update_link_speed pcie_bwnotif_enable pcie_bwnotif_probe pcie_port_probe_service really_probe"
    }
  ],
  "lastModified": "2026-06-17T08:44:53.193",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "E7E864B0-8C00-4679-BA55-659B4C9C3AD3",
              "versionEndExcluding": "6.13.11",
              "versionStartIncluding": "6.13"
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            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "FADAE5D8-4808-442C-B218-77B2CE8780A0",
              "versionEndExcluding": "6.14.2",
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          ],
          "operator": "OR"
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  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}