CVE-2022-49786: blk-cgroup: properly pin the parent in blkcg_css_online

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: 2025-05-01 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: properly pin the parent in blkcg_css_online blkcg_css_online is supposed to pin the blkcg of the parent, but 397c9f46ee4d refactored things and along the way, changed it to pin the css instead. This results in extra pins, and we end up leaking blkcgs and cgroups.

Affected products

Linux kernel: from 5.19 before 6.0.10; 6.1-rc1, 6.1-rc2, 6.1-rc3, 6.1-rc4, 6.1-rc5 — fixed in 6.0.10

How to fix

Upgrade to a fixed version: Linux kernel 6.0.10. Check the vendor advisory for mitigations.

References

https://git.kernel.org/stable/c/d118247e404d6338f7b90636a3c6b95a387ed163
https://git.kernel.org/stable/c/d7dbd43f4a828fa1d9a8614d5b0ac40aee6375fe

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