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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-01-12 · updated 2026-10-26
Weakness: CWE-402

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.

Affected products

Fedoraproject Fedora: 39
Linux kernel: from 6.2 before 6.4; 6.4-rc1, 6.4-rc2, 6.4-rc3, 6.4-rc4, 6.4-rc5, 6.4-rc6 — fixed in 6.4
Red Hat Enterprise Linux: 8.0, 9.0
kernel: before 6.4-rc7 — fixed in 6.4-rc7
Red Hat Enterprise Linux 8: all versions — fixed in 0:4.18.0-513.5.1.el8_9
Red Hat Enterprise Linux 9: all versions
Red Hat Enterprise Linux 9.2 Extended Update Support: all versions — fixed in 0:5.14.0-284.40.1.el9_2

How to fix

Upgrade to a fixed version: Linux kernel 6.4; kernel 6.4-rc7; Red Hat Enterprise Linux 8 0:4.18.0-513.5.1.el8_9; Red Hat Enterprise Linux 9.2 Extended Update Support 0:5.14.0-284.40.1.el9_2. Check the vendor advisory for mitigations.

References

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