CVE-2026-68399
Received Received - Intake

Use-After-Free in Linux Kernel BPF Socket Storage

Vulnerability report for CVE-2026-68399, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix UAF in sock clone early bailouts Similar to recent commit 9b51a6155d14 ("bpf,fork: wipe ->bpf_storage before bailouts that access it"), sk_clone() performs an initial shallow copy of the socket field ->sk_bpf_storage via sock_copy() for the cloned socket newsk. If sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior to calling bpf_sk_storage_clone(), newsk->sk_bpf_storage still points to the parent socket's BPF local storage. When newsk is subsequently freed via sk_free(), the deallocation path (__sk_destruct() -> bpf_sk_storage_free()) destroys the parent socket's BPF local storage, leading to a use-after-free (UAF) on the parent socket. Fix this by resetting newsk->sk_bpf_storage to NULL immediately after sock_copy() in sk_clone(), and remove the now redundant initialization from bpf_sk_storage_clone().

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a use-after-free (UAF) vulnerability in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. It occurs during socket cloning when an early bailout leaves a cloned socket pointing to the parent's BPF storage. When the cloned socket is freed, it incorrectly frees the parent's storage, causing a UAF on the parent socket.

Impact Analysis

This vulnerability could allow an attacker to cause system instability, crashes, or potentially execute arbitrary code with kernel privileges. It affects systems running vulnerable Linux kernel versions with BPF enabled.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for this UAF vulnerability in BPF socket cloning. Monitor kernel security advisories for kernel versions addressing this issue.

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