CVE-2026-43438

sched_ext: Remove redundant css_put() in scx_cgroup_init()

HIGH
7.8
CVSS Score
Published: May 8, 2026 at 02:22 PM UTC
Updated: August 5, 2026 at 01:24 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.1%

Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Remove redundant css_put() in scx_cgroup_init() The iterator css_for_each_descendant_pre() walks the cgroup hierarchy under cgroup_lock(). It does not increment the reference counts on yielded css structs. According to the cgroup documentation, css_put() should only be used to release a reference obtained via css_get() or css_tryget_online(). Since the iterator does not use either of these to acquire a reference, calling css_put() in the error path of scx_cgroup_init() causes a refcount underflow. Remove the unbalanced css_put() to prevent a potential Use-After-Free (UAF) vulnerability.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.12 ≤ v < 6.12.786.12 ≤ v < 6.18.196.12 ≤ v < 6.19.96.12 ≤ v < 7.06.13 ≤ v < 6.18.196.19 ≤ v < 6.19.96.127.0 rc17.0 rc28195136669661fdfe54e9a8923c33b31c92fc1da
Vendor states this is fixed in 1336b579f6079fb8520be03624fcd9ba443c930b (fixed)
Vendor states this is fixed in 6eaaa67d6998f6c30c462b140db8c062e07ec473 (fixed)
Vendor states this is fixed in bf50f3285eda8a0173625fcdb5f183f96e1008cd (fixed)
Vendor states this is fixed in cc095cd305fddbe25a968e4a78436ff9476cf0f6 (fixed)
Vendor states this is fixed in 6.12 (unaffected)
Vendor states this is fixed in 6.12.78 (unaffected)
Vendor states this is fixed in 6.18.19 (unaffected)
Vendor states this is fixed in 6.19.9 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusANALYZED
CWE
CWE-416

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