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CVE-2025-38282

Estado: AnalizadaMedia (5.5)—

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

kernfs: Relax constraint in draining guard

The active reference lifecycle provides the break/unbreak mechanism but the active reference is not truly active after unbreak -- callers don't use it afterwards but it's important for proper pairing of kn->active counting. Assuming this mechanism is in place, the WARN check in kernfs_should_drain_open_files() is too sensitive -- it may transiently catch those (rightful) callers between kernfs_unbreak_active_protection() and kernfs_put_active() as found out by Chen Ridong:

To avoid the false positives (mind panic_on_warn) remove the check altogether. (This is meant as quick fix, I think active reference break/unbreak may be simplified with larger rework.)

Detalles técnicos trazas, registros y código del informe original
	kernfs_remove_by_name_ns	kernfs_get_active // active=1
	__kernfs_remove					  // active=0x80000002
	kernfs_drain			...
	wait_event
	//waiting (active == 0x80000001)
					kernfs_break_active_protection
					// active = 0x80000001
	// continue
					kernfs_unbreak_active_protection
					// active = 0x80000002
	...
	kernfs_should_drain_open_files
	// warning occurs
					kernfs_put_active

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 (2)

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2025-38282",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "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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  },
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          "product": "Linux",
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              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/kernfs/dir.c",
            "fs/kernfs/file.c"
          ],
          "defaultStatus": "affected"
        }
      ]
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  ],
  "published": "2025-07-10T08:15:26.610",
  "references": [
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      "url": "https://git.kernel.org/stable/c/071d8e4c2a3b0999a9b822e2eb8854784a350f8a",
      "tags": [
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      "tags": [
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        "Third Party Advisory"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
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      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkernfs: Relax constraint in draining guard\n\nThe active reference lifecycle provides the break/unbreak mechanism but\nthe active reference is not truly active after unbreak -- callers don't\nuse it afterwards but it's important for proper pairing of kn->active\ncounting. Assuming this mechanism is in place, the WARN check in\nkernfs_should_drain_open_files() is too sensitive -- it may transiently\ncatch those (rightful) callers between\nkernfs_unbreak_active_protection() and kernfs_put_active() as found out by Chen\nRidong:\n\n\tkernfs_remove_by_name_ns\tkernfs_get_active // active=1\n\t__kernfs_remove\t\t\t\t\t  // active=0x80000002\n\tkernfs_drain\t\t\t...\n\twait_event\n\t//waiting (active == 0x80000001)\n\t\t\t\t\tkernfs_break_active_protection\n\t\t\t\t\t// active = 0x80000001\n\t// continue\n\t\t\t\t\tkernfs_unbreak_active_protection\n\t\t\t\t\t// active = 0x80000002\n\t...\n\tkernfs_should_drain_open_files\n\t// warning occurs\n\t\t\t\t\tkernfs_put_active\n\nTo avoid the false positives (mind panic_on_warn) remove the check altogether.\n(This is meant as quick fix, I think active reference break/unbreak may be\nsimplified with larger rework.)"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: kernfs: relajar restricción en el drenaje de la protección El ciclo de vida de la referencia activa proporciona el mecanismo de interrupción/desconexión, pero la referencia activa no está verdaderamente activa después de la conexión; los llamadores no la usan después, pero es importante para el emparejamiento adecuado del conteo kn->activo. Suponiendo que este mecanismo está en su lugar, la comprobación WARN en kernfs_should_drain_open_files() es demasiado sensible - puede atrapar transitoriamente a aquellos llamadores (legítimos) entre kernfs_unbreak_active_protection() y kernfs_put_active() como descubrió Chen Ridong: kernfs_remove_by_name_ns kernfs_get_active // active=1 __kernfs_remove // active=0x80000002 kernfs_drain ... wait_event //waiting (active == 0x80000001) kernfs_break_active_protection // active = 0x80000001 // continuar kernfs_unbreak_active_protection // active = 0x80000002 ... kernfs_should_drain_open_files // ocurre una advertencia kernfs_put_active Para evitar los falsos positivos (tenga en cuenta \"panic_on_warn\"), elimine la comprobación por completo. (Esto es una solución rápida; creo que la interrupción/desconexión de referencias activas se puede simplificar con una revisión más exhaustiva)."
    }
  ],
  "lastModified": "2026-06-17T09:16:32.667",
  "configurations": [
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