# CVE-2024-0443: Kernel: blkio memory leakage due to blkcg and some blkgs are not freed after they are made offline.

Status: published. Published: 2024-01-11. Updated: 2026-11-05.

A flaw was found in the blkgs destruction path in block/blk-cgroup.c in the Linux kernel, leading to a cgroup blkio memory leakage problem. When a cgroup is being destroyed, cgroup_rstat_flush() is only called at css_release_work_fn(), which is called when the blkcg reference count reaches 0. This circular dependency will prevent blkcg and some blkgs from being freed after they are made offline. This issue may allow an attacker with a local access to cause system instability, such as an out of memory error.

## Remediation

- workaround: This flaw can be mitigated with the possible workaround identified below:

- systemd.unified_cgroup_hierarchy=1

or

- cgroup_disable=blkio (source: CNA: redhat)

## Affected products and versions

-  /  (kernel): ≥ 0; < 6.4-rc7 (affected, semver). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (kernel): ≥ 0:4.18.0-513.5.1.el8_9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Extended Update Support (kernel): ≥ 0:5.14.0-284.40.1.el9_2; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (kernel-rt): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (kernel-rt): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (kernel-rt): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.25% as of 2026-11-04; percentile 16.40%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-402

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2023:6583 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2023:7077 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2023:7370 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2024-0443 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2257968 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://lore.kernel.org/linux-block/20221215033132.230023-3-longman@redhat.com/ (CNA: redhat)

- https://access.redhat.com/errata/RHSA-2023:6583 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/errata/RHSA-2023:7077 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/errata/RHSA-2023:7370 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/security/cve/CVE-2024-0443 (ADP: CVE; vdb-entry, x_refsource_REDHAT, x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=2257968 (ADP: CVE; issue-tracking, x_refsource_REDHAT, x_transferred)

- https://lore.kernel.org/linux-block/20221215033132.230023-3-longman@redhat.com/ (ADP: CVE; x_transferred)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2024-0443; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2024-0443; retrieved 2026-11-05; source updated Not reported

Revision: 6977829a91861639dfeb42a979be141b042e96253106b4ba365e1c0f1c62e57c

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