CVE-2026-90325
In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: skip dying blkg in blkcg_activate_policy() When switching IO schedulers on a block device, blkcg_activate_policy() can race with concurrent blkcg deletion, leading to a use-after-free in rcu_accelerate_cbs. T1: T2: blkg_destroy kill(&blkg->refcnt) // blkg->refcnt=1->0 blkg_release // call_rcu(__blkg_release) ... blkg_free_workfn ->pd_free_fn(pd) elv_iosched_store elevator_switch ... iterate blkg list blkg_get(blkg) // blkg->refcnt=0->1 list_del_init(&blkg->q_node) blkg_put(pinned_blkg) // blkg->refcnt=1->0 blkg_release // call_rcu again rcu_accelerate_cbs // uaf Fix this by checking hlist_unhashed(&blkg->blkcg_node) before getting a reference to the blkg. This is the same check used in blkg_destroy() to detect if a blkg has already been destroyed. If the blkg is already unhashed, skip processing it since it's being destroyed.
- CVSS 3.1
- 7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 5% of CVEs (scores of 2026-10-25)
- Published
- Modified
- Record from
- the NVD, synced
References
- https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df
- https://git.kernel.org/stable/c/1a267295b1ea6a6477963f3fda84adfecd48fcad
- https://git.kernel.org/stable/c/3d8c3da95c75a4d312e272fc7b4076dd3ba9115c
- https://git.kernel.org/stable/c/5e9220389920f33b6a804d50c548cd0cd1b04634
- https://git.kernel.org/stable/c/7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d