blk-cgroup: dropping parent refcount after pd_free_fn() is done

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2023-54107
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-24 13:16:12 UTC
Updated2026-10-15 22:17:53 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: blk-cgroup: dropping parent refcount after pd_free_fn() is done Some cgroup policies will access parent pd through child pd even after pd_offline_fn() is done. If pd_free_fn() for parent is called before child, then UAF can be triggered. Hence it's better to guarantee the order of pd_free_fn(). Currently refcount of parent blkg is dropped in __blkg_release(), which is before pd_free_fn() is called in blkg_free_work_fn() while blkg_free_work_fn() is called asynchronously. This patch make sure pd_free_fn() called from removing cgroup is ordered by delaying dropping parent refcount after calling pd_free_fn() for child. BTW, pd_free_fn() will also be called from blkcg_deactivate_policy() from deleting device, and following patches will guarantee the order.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001320000 probability, percentile 0.031310000 (date 2026-08-06)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected d578c770c85233af592e54537f93f3831bde7e9a c7241babf0855d8a6180cd1743ff0ec34de40b4e git Not specified
CNA Linux Linux affected 5.18 Not specified
CNA Linux Linux unaffected 5.18 semver Not specified
CNA Linux Linux unaffected 6.3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/c7241babf0855d8a6180cd1743ff0ec34de40b4e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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