Kernel use-after-free via unlocked BFQ queue dereference
Published Dec 27, 2024 · Updated Aug 5, 2026
Use-after-free in the BFQ I/O scheduler in affected Linux kernels allows local users to trigger invalid kernel-memory access through concurrent I/O. bfq_limit_depth() reads a bfqq pointer from a shared io_context without holding bfqd->lock while another task can free or replace that queue. The race requires multiple tasks to share an I/O context; io_uring reproduced a KASAN slab-use-after-free, and Siemens embeds the affected kernel in firmware 3.1.5 and later.
Summary
What happened
Use-after-free in the BFQ I/O scheduler in affected Linux kernels allows local users to trigger invalid kernel-memory access through concurrent I/O. bfq_limit_depth() reads a bfqq pointer from a shared io_context without holding bfqd->lock while another task can free or replace that queue. The race requires multiple tasks to share an I/O context; io_uring reproduced a KASAN slab-use-after-free, and Siemens embeds the affected kernel in firmware 3.1.5 and later.
The record
- CVE
- CVE-2024-53166
- Published
- Dec 27, 2024
- Updated
- Aug 5, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-416
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 27, 2024CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=V3.1.5 <*
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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