CVE-2026-43438: Linux kernel · sched_ext: Remove redundant css_put() in scx_cgroup_init()
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 27 Oct 2026, 00:07 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 8 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
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.
References
- nvd.nist.gov/vuln/detail/CVE-2026-43438 (opens in a new tab)
- git.kernel.org/stable/c/1336b579f6079fb8520be03624fcd9ba443c930b (opens in a new tab)
- git.kernel.org/stable/c/6eaaa67d6998f6c30c462b140db8c062e07ec473 (opens in a new tab)
- git.kernel.org/stable/c/bf50f3285eda8a0173625fcdb5f183f96e1008cd (opens in a new tab)
- git.kernel.org/stable/c/cc095cd305fddbe25a968e4a78436ff9476cf0f6 (opens in a new tab)