Kernel control via nftables route double release
Published May 17, 2024 · Updated Aug 5, 2026
Use-after-free in the nftables flow offload path of the Linux kernel allows local users to gain kernel control via crafted traffic. When flow_offload_add() rejects a duplicate tuple, nft_flow_offload leaves a transferred dst pointer in its route object and the error path releases it twice. A user namespace supplies the required CAP_NET_ADMIN; triggering the deterministic collision can disclose or overwrite kernel memory or cause an oops or panic.
Summary
What happened
Use-after-free in the nftables flow offload path of the Linux kernel allows local users to gain kernel control via crafted traffic. When flow_offload_add() rejects a duplicate tuple, nft_flow_offload leaves a transferred dst pointer in its route object and the error path releases it twice. A user namespace supplies the required CAP_NET_ADMIN; triggering the deterministic collision can disclose or overwrite kernel memory or cause an oops or panic.
The record
- CVE
- CVE-2024-27403
- Published
- May 17, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 17, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.16
- Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <012df10717da02367aaf92c65f9c89db206c15f4
- Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <4c167af9f6b5ae4a5dbc243d5983c295ccc2e43c
- Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <558b00a30e05753a62ecc7e05e939ca8f0241148
- Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <670548c8db44d76e40e1dfc06812bca36a61e9ae
- Affected versionversion=a3c90f7a2323b331ae816d5b0633e68148e25d04 <9e0f0430389be7696396c62f037be4bf72cf93e3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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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