CVE-2026-74549

Estado: RecibidaAlta (7.8)—

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

hwmon: (nct6775-core) Prevent access to unsupported weight registers

Sashiko reports:

During initialization of the nct6116 chip, the driver sets data->pwm_num to 5. However, it assigns several NCT6106 register arrays (such as NCT6106_REG_WEIGHT_DUTY_STEP, NCT6106_REG_WEIGHT_TEMP_SEL, and NCT6106_REG_WEIGHT_TEMP_*) to data->REG_PWM and data->REG_WEIGHT_TEMP. These arrays only contain 3 elements.

In nct6775_update_pwm(), the driver iterates up to data->pwm_num. If data->has_pwm has bits 3 or 4 set (which is structurally possible for nct6116), the loop attempts to read elements at index 3 and 4 from these 3-element arrays. This results in a global out-of-bounds read, which can be caught by KASAN.

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Furthermore, the driver uses these garbage out-of-bounds values as hardware register addresses for subsequent read and write operations. This leads to invalid hardware register access, potentially causing hardware misconfiguration or system crashes.

The underlying problem is that the chip does support up to five fan control channels, but only the first three support weight control. Fix the problem by extending the affected weight register arrays with zeroed fields. The driver uses zeroed register addresses to determine if a register is supported or not, and skips accesses for unsupported registers.

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: 0.18%
Percentil entre todas las CVEs puntuadas: 6
Fecha de la puntuación: 6/10/2026

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 principalT1499.004 Application or System Exploitationimpact65 %
Impacto secundarioT1565.001 Stored Data Manipulationimpact60 %

Vulnerabilidad de acceso local sin interacción (AV:L, PR:L, UI:N) en kernel Linux que permite lectura/escritura de memoria fuera de límites, causando caída del sistema o corrupción de hardware.

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 Restrict File and Directory Permissions Remote Data Storage Filter Network Traffic Execution Prevention Encrypt Sensitive Information

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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  "id": "CVE-2026-74549",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
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          "version": "3.1",
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          "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",
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  "published": "2026-08-15T13:18:00.270",
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  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (nct6775-core) Prevent access to unsupported weight registers\n\nSashiko reports:\n\nDuring initialization of the nct6116 chip, the driver sets data->pwm_num\nto 5. However, it assigns several NCT6106 register arrays (such as\nNCT6106_REG_WEIGHT_DUTY_STEP, NCT6106_REG_WEIGHT_TEMP_SEL, and\nNCT6106_REG_WEIGHT_TEMP_*) to data->REG_PWM and data->REG_WEIGHT_TEMP.\nThese arrays only contain 3 elements.\n\nIn nct6775_update_pwm(), the driver iterates up to data->pwm_num. If\ndata->has_pwm has bits 3 or 4 set (which is structurally possible for\nnct6116), the loop attempts to read elements at index 3 and 4 from these\n3-element arrays. This results in a global out-of-bounds read, which can\nbe caught by KASAN.\n\nFurthermore, the driver uses these garbage out-of-bounds values as\nhardware register addresses for subsequent read and write operations. This\nleads to invalid hardware register access, potentially causing hardware\nmisconfiguration or system crashes.\n\nThe underlying problem is that the chip does support up to five fan\ncontrol channels, but only the first three support weight control.\nFix the problem by extending the affected weight register arrays with\nzeroed fields. The driver uses zeroed register addresses to determine\nif a register is supported or not, and skips accesses for unsupported\nregisters."
    }
  ],
  "lastModified": "2026-08-19T17:21:09.840",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}