Local privilege escalation via stale class reference
Published Sep 6, 2023 · Updated Feb 13, 2025
Use-after-free in Linux Kernel 3.18 through 6.4 allows local users to gain elevated privileges through a cls_route filter update. The route4_change() path copies the old tcf_result into a replacement filter, then tcf_unbind_filter() decrements the still-referenced class count so the class can be freed while referenced. Exploitation requires local low-privileged access and an unprivileged user namespace; successful exploitation grants elevated privileges on the host.
Summary
What happened
Use-after-free in Linux Kernel 3.18 through 6.4 allows local users to gain elevated privileges through a cls_route filter update. The route4_change() path copies the old tcf_result into a replacement filter, then tcf_unbind_filter() decrements the still-referenced class count so the class can be freed while referenced. Exploitation requires local low-privileged access and an unprivileged user namespace; successful exploitation grants elevated privileges on the host.
The record
- CVE
- CVE-2023-4206
- Published
- Sep 6, 2023
- Updated
- Feb 13, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 6, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 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=3.18 <6.5
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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Public exploit references
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Technologies
Your stack
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Your stack
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