Local root escalation via tcindex update race
Published Mar 22, 2023 · Updated Jul 30, 2026
Use-after-free in Linux Kernel allows local users to gain root privileges by racing tcindex imperfect-hash filter updates. tcindex_change replaces an existing filter's extensions and frees the old tcf_ext before an RCU grace period, so concurrent packet traversal can pass the stale object to tcf_exts_exec(). Exploitation requires CAP_NET_ADMIN, commonly available through unprivileged user namespaces, and successful exploitation grants root privileges.
Summary
What happened
Use-after-free in Linux Kernel allows local users to gain root privileges by racing tcindex imperfect-hash filter updates. tcindex_change replaces an existing filter's extensions and frees the old tcf_ext before an RCU grace period, so concurrent packet traversal can pass the stale object to tcf_exts_exec(). Exploitation requires CAP_NET_ADMIN, commonly available through unprivileged user namespaces, and successful exploitation grants root privileges.
The record
- CVE
- CVE-2023-1281
- Published
- Mar 22, 2023
- Updated
- Jul 30, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 22, 2023CVE publishedPublication date reported by the CVE source.
- Jul 30, 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=4.14.0 <5.10.169
- Affected versionversion=5.11.0 <5.15.95
- Affected versionversion=5.16.0 <6.1.13
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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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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