Local kernel memory corruption via dangling socket pointer
Published Jul 12, 2024 · Updated Aug 5, 2026
Use-after-free in affected Linux kernel branches from 5.12 allows local users to read or corrupt reclaimed kernel heap memory. When socket creation fails after sock_init_data(), sk_common_release() leaves socket->sk pointing to a freed struct sock, and an fentry probe invoking bpf_get_socket_cookie() dereferences it. Exposure requires host-installed socket-lifecycle eBPF instrumentation; an unprivileged process can then trigger kernel-data disclosure, heap corruption, or a panic through a failing socket syscall.
Summary
What happened
Use-after-free in affected Linux kernel branches from 5.12 allows local users to read or corrupt reclaimed kernel heap memory. When socket creation fails after sock_init_data(), sk_common_release() leaves socket->sk pointing to a freed struct sock, and an fentry probe invoking bpf_get_socket_cookie() dereferences it. Exposure requires host-installed socket-lifecycle eBPF instrumentation; an unprivileged process can then trigger kernel-data disclosure, heap corruption, or a panic through a failing socket syscall.
The record
- CVE
- CVE-2024-40954
- Published
- Jul 12, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 12, 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=5.12
- Affected versionversion=c5dbb89fc2ac013afe67b9e4fcb3743c02b567cd <454c454ed645fed051216b79622f7cb69c1638f5
- Affected versionversion=c5dbb89fc2ac013afe67b9e4fcb3743c02b567cd <5dfe2408fd7dc4d2e7ac38a116ff0a37b1cfd3b9
- Affected versionversion=c5dbb89fc2ac013afe67b9e4fcb3743c02b567cd <6cd4a78d962bebbaf8beb7d2ead3f34120e3f7b2
- Affected versionversion=c5dbb89fc2ac013afe67b9e4fcb3743c02b567cd <78e4aa528a7b1204219d808310524344f627d069
- Affected versionversion=c5dbb89fc2ac013afe67b9e4fcb3743c02b567cd <893eeba94c40d513cd0fe6539330ebdaea208c0e
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.
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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