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CVE-2026-31734

Estado: AnalizadaMedia (5.5)—

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

sched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU

Since commit 8e4f0b1ebcf2 ("bpf: use rcu_read_lock_dont_migrate() for trampoline.c"), the BPF prolog (__bpf_prog_enter) calls migrate_disable() only when CONFIG_PREEMPT_RCU is enabled, via rcu_read_lock_dont_migrate(). Without CONFIG_PREEMPT_RCU, the prolog never touches migration_disabled, so migration_disabled == 1 always means the task is truly migration-disabled regardless of whether it is the current task.

The old unconditional p == current check was a false negative in this case, potentially allowing a migration-disabled task to be dispatched to a remote CPU and triggering scx_error in task_can_run_on_remote_rq().

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Only apply the p == current disambiguation when CONFIG_PREEMPT_RCU is enabled, where the ambiguity with the BPF prolog still exists.

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 (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU\n\nSince commit 8e4f0b1ebcf2 (\"bpf: use rcu_read_lock_dont_migrate() for\ntrampoline.c\"), the BPF prolog (__bpf_prog_enter) calls migrate_disable()\nonly when CONFIG_PREEMPT_RCU is enabled, via rcu_read_lock_dont_migrate().\nWithout CONFIG_PREEMPT_RCU, the prolog never touches migration_disabled,\nso migration_disabled == 1 always means the task is truly\nmigration-disabled regardless of whether it is the current task.\n\nThe old unconditional p == current check was a false negative in this\ncase, potentially allowing a migration-disabled task to be dispatched to\na remote CPU and triggering scx_error in task_can_run_on_remote_rq().\n\nOnly apply the p == current disambiguation when CONFIG_PREEMPT_RCU is\nenabled, where the ambiguity with the BPF prolog still exists."
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  "lastModified": "2026-06-17T10:34:20.003",
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