CVE-2025-38282
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
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.18%
- Percentil entre todas las CVEs puntuadas: 7
- 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).
Tecnologías afectadas (2)
CWE
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/071d8e4c2a3b0999a9b822e2eb8854784a350f8a
- https://git.kernel.org/stable/c/2d6a67c2b3b87808a347dc1047b520a9dd177a4f
- https://git.kernel.org/stable/c/6bfb154f95d5f0ab7ed056f23aba8c1a94cb3927
- https://git.kernel.org/stable/c/6c81f1c7812c61f187bed1b938f1d2e391d503ab
- https://git.kernel.org/stable/c/72275c888f8962b406ee9c6885c79bf68cca5a63
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
JSON original (NVD)
Mostrar
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"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.)"
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"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",
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