Kernel crash via netlink object-release race
Published May 1, 2025 · Updated Aug 5, 2026
A race condition in Linux 5.12, affected later 5.x releases, and 6.1 release candidates allows local users to crash the kernel. The nft_rcv_nl_event notifier can remove objects still referenced by the lockless nf_tables commit-release path after deferred destruction. Triggering the race requires local low-privileged netlink access and produces a use-after-free read that can terminate the running kernel.
Summary
What happened
A race condition in Linux 5.12, affected later 5.x releases, and 6.1 release candidates allows local users to crash the kernel. The nft_rcv_nl_event notifier can remove objects still referenced by the lockless nf_tables commit-release path after deferred destruction. Triggering the race requires local low-privileged netlink access and produces a use-after-free read that can terminate the running kernel.
The record
- CVE
- CVE-2022-49920
- Published
- May 1, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-362, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 1, 2025CVE 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.12
- Affected versionversion=6001a930ce0378b62210d4f83583fc88a903d89d <1ffe7100411a8b9015115ce124cd6c9c9da6f8e3
- Affected versionversion=6001a930ce0378b62210d4f83583fc88a903d89d <d4bc8271db21ea9f1c86a1ca4d64999f184d4aae
- Affected versionversion=6001a930ce0378b62210d4f83583fc88a903d89d <e40b7c44d19e327ad8b49a491ef1fa8dcc4566e0
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
- syzkaller nf_tables use-after-free C reproducerfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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