CVE-2026-43438

Kernel memory corruption via unbalanced css_put

Published May 8, 2026 · Updated May 8, 2026

Use after free in Linux Kernel allows local users with BPF access to corrupt kernel memory through the sched_ext cgroup initialization path. The scx_cgroup_init() error path calls css_put() on a css_for_each_descendant_pre() result even though the iterator acquired no reference, underflowing the cgroup subsystem-state reference count and enabling stale-object use. Loading and attaching sched_ext BPF struct_ops is required; resulting kernel-memory corruption can disclose memory, alter kernel state, or crash the system.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use after free in Linux Kernel allows local users with BPF access to corrupt kernel memory through the sched_ext cgroup initialization path. The scx_cgroup_init() error path calls css_put() on a css_for_each_descendant_pre() result even though the iterator acquired no reference, underflowing the cgroup subsystem-state reference count and enabling stale-object use. Loading and attaching sched_ext BPF struct_ops is required; resulting kernel-memory corruption can disclose memory, alter kernel state, or crash the system.

The record

CVE
CVE-2026-43438
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.12
  2. Affected versionversion=8195136669661fdfe54e9a8923c33b31c92fc1da <1336b579f6079fb8520be03624fcd9ba443c930b
  3. Affected versionversion=8195136669661fdfe54e9a8923c33b31c92fc1da <6eaaa67d6998f6c30c462b140db8c062e07ec473
  4. Affected versionversion=8195136669661fdfe54e9a8923c33b31c92fc1da <bf50f3285eda8a0173625fcdb5f183f96e1008cd
  5. Affected versionversion=8195136669661fdfe54e9a8923c33b31c92fc1da <cc095cd305fddbe25a968e4a78436ff9476cf0f6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.12; version=8195136669661fdfe54e9a8923c33b31c92fc1da <1336b579f6079fb8520be03624fcd9ba443c930b; version=8195136669661fdfe54e9a8923c33b31c92fc1da <6eaaa67d6998f6c30c462b140db8c062e07ec473; version=8195136669661fdfe54e9a8923c33b31c92fc1da <bf50f3285eda8a0173625fcdb5f183f96e1008cd; version=8195136669661fdfe54e9a8923c33b31c92fc1da <cc095cd305fddbe25a968e4a78436ff9476cf0f6

Published CVSS scores

4.1OracleCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo