CVE-2026-74601

Estado: RecibidaAlta (7.8)—

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

ring-buffer: Use current_context for safe per-CPU buffer swap

The ring_buffer_swap_cpu() function currently checks the per-CPU committing counter to determine if a buffer is actively being written to before performing the swap. However, there exists a race window where this check can be bypassed:

The committing counter can temporarily drop to 0 during a single write operation (within rb_move_tail), creating a window where swap can succeed even though the write is still in progress. This leads to inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().

Leer descripción completaMostrar menos

Replace the committing counter check with current_context checks, which are set at the entry of ring_buffer_lock_reserve() and remain valid throughout the entire write operation, providing a reliable indicator of buffer busy state during swap.

Detalles técnicos trazas, registros y código del informe original

    ring_buffer_lock_reserve
        cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a
        rb_reserve_next_event
            rb_start_commit // inc committing
            if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
            __rb_reserve_next
                rb_move_tail
                    rb_end_commit(cpu_buffer);   // dec committing => 0
                    /* interrupt hits here, successfully swaps! */
                    local_inc(&cpu_buffer->committing);

    ring_buffer_unlock_commit
        cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b
        rb_commit
            rb_end_commit
            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
                                                // triggers warning

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: 0.14%
Percentil entre todas las CVEs puntuadas: 3
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 %
Impacto secundarioT1565.001 Stored Data Manipulationimpact70 %

Vulnerabilidad de escalada local (AV:L, PR:L, UI:N) en kernel Linux por condición de carrera en ring_buffer. Permite DoS o corrupción de datos de buffer.

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-2026-74601",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "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
      }
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      "affectedData": [
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          "product": "Linux",
          "versions": [
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              "version": "5.15.217",
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            },
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              "version": "6.1.184",
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              "status": "unaffected",
              "version": "6.6.153",
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            {
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              "version": "6.12.105",
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              "version": "7.1.9",
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            },
            {
              "status": "unaffected",
              "version": "7.2",
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              "lessThanOrEqual": "*"
            }
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          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-22T16:16:32.530",
  "references": [
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      "url": "https://git.kernel.org/stable/c/22709117d9ae95e52673685f98caac7c356a8227",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Use current_context for safe per-CPU buffer swap\n\nThe ring_buffer_swap_cpu() function currently checks the per-CPU\ncommitting counter to determine if a buffer is actively being written to\nbefore performing the swap. However, there exists a race window where\nthis check can be bypassed:\n\n    ring_buffer_lock_reserve\n        cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a\n        rb_reserve_next_event\n            rb_start_commit // inc committing\n            if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}\n            __rb_reserve_next\n                rb_move_tail\n                    rb_end_commit(cpu_buffer);   // dec committing => 0\n                    /* interrupt hits here, successfully swaps! */\n                    local_inc(&cpu_buffer->committing);\n\n    ring_buffer_unlock_commit\n        cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b\n        rb_commit\n            rb_end_commit\n            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))\n                                                // triggers warning\n\nThe committing counter can temporarily drop to 0 during a single write\noperation (within rb_move_tail), creating a window where swap can\nsucceed even though the write is still in progress. This leads to\ninconsistent buffer state and triggers the RB_WARN_ON in rb_commit().\n\nReplace the committing counter check with current_context checks, which\nare set at the entry of ring_buffer_lock_reserve() and remain valid\nthroughout the entire write operation, providing a reliable indicator of\nbuffer busy state during swap."
    }
  ],
  "lastModified": "2026-08-25T06:18:36.057",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}