Vulnerability Database

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Total vulnerabilities in the database

CVE-2026-53328 — linux / linux_kernel

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

sched_ext: Don't warn on NULL cgrp_moving_from in scx_cgroup_move_task()

A WARN fires when systemd's user manager writes "+cpu +memory +pids" to its own subtree_control while a sched_ext scheduler is loaded:

WARNING: at kernel/sched/ext.c:3227 scx_cgroup_move_task+0xa8/0xb0 scx_cgroup_move_task+0xa8/0xb0 sched_move_task+0x134/0x290 cpu_cgroup_attach+0x39/0x70 cgroup_migrate_execute+0x37d/0x450 cgroup_update_dfl_csses+0x1e3/0x270 cgroup_subtree_control_write+0x3e7/0x440

scx_cgroup_can_attach() arms cgrp_moving_from only when a task's cpu cgroup changes. It can still be NULL when scx_cgroup_move_task() runs, through this sequence:

Step Result


  1. cpu enabled on cgroup G cpu css = A
  2. cpu toggled off then on for G A killed, B created (same cgroup)
  3. an exiting task keeps A alive migration skips it, A now stale
  4. +memory migrates G stale A vs current B pulls cpu in
  5. cpu attach runs for all tasks hits a live, cpu-unchanged task
  6. scx_cgroup_move_task() on it cgrp_moving_from NULL -> WARN

The mismatch is that scx_cgroup_can_attach() keys on cgroup identity while migration drives the move on css identity, so a NULL cgrp_moving_from here is a legitimate css-only migration, not a missing prep.

The call is already gated on cgrp_moving_from, so just drop the warning. ops.cgroup_prep_move() and ops.cgroup_move() stay paired.

  • Published: Jul 1, 2026
  • Updated: Jul 24, 2026
  • CVE: CVE-2026-53328
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.5
  • AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

No CWE or OWASP classifications available.

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