CVE-2026-31458

Estado: AnalizadaMedia (5.5)—

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

mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]

Multiple sysfs command paths dereference contexts_arr[0] without first verifying that kdamond->contexts->nr == 1. A user can set nr_contexts to 0 via sysfs while DAMON is running, causing NULL pointer dereferences.

In more detail, the issue can be triggered by privileged users like below.

First, start DAMON and make contexts directory empty (kdamond->contexts->nr == 0).

Then, each of below commands will cause the NULL pointer dereference.

Guard all commands (except OFF) at the entry point of damon_sysfs_handle_cmd().

Detalles técnicos trazas, registros y código del informe original

    # damo start
    # cd /sys/kernel/mm/damon/admin/kdamonds/0
    # echo 0 > contexts/nr_contexts

    # echo update_schemes_stats > state
    # echo update_schemes_tried_regions > state
    # echo update_schemes_tried_bytes > state
    # echo update_schemes_effective_quotas > state
    # echo update_tuned_intervals > state

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: 0.16%
Percentil entre todas las CVEs puntuadas: 5
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).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-476

Referencias

JSON original (NVD)

Mostrar

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond->contexts->nr == 1.  A user can set nr_contexts to\n0 via sysfs while DAMON is running, causing NULL pointer dereferences.\n\nIn more detail, the issue can be triggered by privileged users like\nbelow.\n\nFirst, start DAMON and make contexts directory empty\n(kdamond->contexts->nr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 > contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats > state\n    # echo update_schemes_tried_regions > state\n    # echo update_schemes_tried_bytes > state\n    # echo update_schemes_effective_quotas > state\n    # echo update_tuned_intervals > state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd()."
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