CVE-2023-54107
Unknown Unknown - Not Provided
Use-After-Free Vulnerability in Linux Kernel blk-cgroup Component

Publication date: 2025-12-24

Last updated on: 2025-12-24

Assigner: kernel.org

Description
In 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.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2025-12-24
Last Modified
2025-12-24
Generated
2026-05-27
AI Q&A
2025-12-24
EPSS Evaluated
2026-05-25
NVD
CVE-2023-54107
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability in the Linux kernel involves a use-after-free (UAF) issue related to the blk-cgroup subsystem. Specifically, some cgroup policies access the parent's page directory (pd) through the child's pd even after the child's pd_offline_fn() has completed. If the parent's pd_free_fn() is called before the child's, it can trigger a UAF condition. The problem arises because the reference count of the parent block group (blkg) is dropped asynchronously before pd_free_fn() is called, leading to potential premature freeing. The fix ensures the correct order by delaying dropping the parent's refcount until after pd_free_fn() is called for the child, preventing the UAF.


How can this vulnerability impact me? :

This vulnerability can lead to a use-after-free condition in the Linux kernel's blk-cgroup subsystem, which may cause system instability, crashes, or potentially allow an attacker to execute arbitrary code or escalate privileges if exploited. Such kernel-level vulnerabilities can compromise system security and reliability.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, update your Linux kernel to a version that includes the patch fixing the blk-cgroup parent refcount issue. This patch ensures the correct order of pd_free_fn() calls to prevent use-after-free conditions. Applying the latest kernel updates from your distribution or vendor is recommended.


Ask Our AI Assistant
Need more information? Ask your question to get an AI reply (Powered by our expertise)
0/70
EPSS Chart