CVE-2026-43438 Affecting kernel6.18-libbpf-debuginfo package, versions <1:6.18.20-20.229.amzn2023
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-AMZN2023-KERNEL618LIBBPFDEBUGINFO-16735178
- published18 May 2026
- disclosed8 May 2026
Introduced: 8 May 2026
NewCVE-2026-43438 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 kernel6.18-libbpf-debuginfo to version 1:6.18.20-20.229.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1596.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel6.18-libbpf-debuginfo package and not the kernel6.18-libbpf-debuginfo package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
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
- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-43438
- https://git.kernel.org/stable/c/1336b579f6079fb8520be03624fcd9ba443c930b
- https://git.kernel.org/stable/c/6eaaa67d6998f6c30c462b140db8c062e07ec473
- https://git.kernel.org/stable/c/bf50f3285eda8a0173625fcdb5f183f96e1008cd
- https://git.kernel.org/stable/c/cc095cd305fddbe25a968e4a78436ff9476cf0f6