Local kernel panic via cleared iostat pointers
Published Sep 18, 2025 · Updated Sep 18, 2025
A NULL pointer dereference in the Linux kernel allows local users to panic the host by resetting cgroup v1 block I/O statistics. blkcg_reset_stats() clears each blkg_iostat_set without restoring its blkg pointer and sync field, so later accounting dereferences a NULL blkg pointer. The path requires local access to write blkio.reset_stats; successful exploitation interrupts the host, while debug builds can also report uninitialized lock state.
Summary
What happened
A NULL pointer dereference in the Linux kernel allows local users to panic the host by resetting cgroup v1 block I/O statistics. blkcg_reset_stats() clears each blkg_iostat_set without restoring its blkg pointer and sync field, so later accounting dereferences a NULL blkg pointer. The path requires local access to write blkio.reset_stats; successful exploitation interrupts the host, while debug builds can also report uninitialized lock state.
The record
- CVE
- CVE-2023-53421
- Published
- Sep 18, 2025
- Updated
- Sep 18, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-476, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 18, 2025CVE publishedPublication date reported by the CVE source.
- Sep 18, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.5
- Affected versionversion=f73316482977ac401ac37245c9df48079d4e11f3 <3d2af77e31ade05ff7ccc3658c3635ec1bea0979
- Affected versionversion=f73316482977ac401ac37245c9df48079d4e11f3 <abbce7f82613ea5eeefd0fc3c1c8e449b9cef2a2
- Affected versionversion=f73316482977ac401ac37245c9df48079d4e11f3 <b0d26283af612b9e0cc3188b0b88ad7fdea447e8
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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