Local privilege escalation via route4_change use-after-free
Published Mar 2, 2022 · Updated Aug 3, 2024
Use-after-free in the Linux kernel before 5.10 allows local users to escalate privileges by changing Traffic Control classification filters. In net/sched/cls_route.c, route4_change() inserts a replacement filter but mistakenly removes the new filter instead of the old one, causing double-free and use-after-free conditions. Exploitation requires CAP_NET_ADMIN; unprivileged user and network namespaces can grant that capability and expose the flaw to otherwise unprivileged local users.
Summary
What happened
Use-after-free in the Linux kernel before 5.10 allows local users to escalate privileges by changing Traffic Control classification filters. In net/sched/cls_route.c, route4_change() inserts a replacement filter but mistakenly removes the new filter instead of the old one, causing double-free and use-after-free conditions. Exploitation requires CAP_NET_ADMIN; unprivileged user and network namespaces can grant that capability and expose the flaw to otherwise unprivileged local users.
The record
- CVE
- CVE-2021-3715
- Published
- Mar 2, 2022
- Updated
- Aug 3, 2024
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 2, 2022CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=Linux kernel 5.10
What conditions does exploitation require?
What is affected?
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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