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CVE-2022-49995

Estado: ModificadaAlta (7.8)—

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

writeback: avoid use-after-free after removing device

When a disk is removed, bdi_unregister gets called to stop further writeback and wait for associated delayed work to complete. However, wb_inode_writeback_end() may schedule bandwidth estimation dwork after this has completed, which can result in the timer attempting to access the just freed bdi_writeback.

Fix this by checking if the bdi_writeback is alive, similar to when scheduling writeback work.

Since this requires wb->work_lock, and wb_inode_writeback_end() may get called from interrupt, switch wb->work_lock to an irqsafe lock.

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

AV:L, PR:L, UI:N indica escalada local sin interacción. La vulnerabilidad de use-after-free (CWE-416) en writeback del kernel permite ejecución de código con privilegios elevados tras manipular dispositivos.

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

Execution PreventionThreat Intelligence ProgramRestrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationBehavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwriteback: avoid use-after-free after removing device\n\nWhen a disk is removed, bdi_unregister gets called to stop further\nwriteback and wait for associated delayed work to complete.  However,\nwb_inode_writeback_end() may schedule bandwidth estimation dwork after\nthis has completed, which can result in the timer attempting to access the\njust freed bdi_writeback.\n\nFix this by checking if the bdi_writeback is alive, similar to when\nscheduling writeback work.\n\nSince this requires wb->work_lock, and wb_inode_writeback_end() may get\ncalled from interrupt, switch wb->work_lock to an irqsafe lock."
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    }
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  "lastModified": "2026-08-04T10:18:02.403",
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