In the Linux kernel, the following vulnerability has been resolved: tcp: Fix out-of-bounds access for twsk in tcp_ao_established_key(). lockdep_sock_is_held() was added in tcp_ao_established_key() by the cited commit. It can be called from tcp_v[46]_timewait_ack() with twsk. Since it does not have sk->sk_lock, the lockdep annotation results in out-of-bound access. $ pahole -C tcp_timewait_sock vmlinux | grep size /* size: 288, cachelines: 5, members: 8 */ $ pahole -C sock vmlinux | grep sk_lock socket_lock_t sk_lock; /* 440 192 */ Let's not use lockdep_sock_is_held() for TCP_TIME_WAIT.

A flaw was found in the Linux kernel's TCP implementation. An out-of-bounds access vulnerability exists when the `lockdep_sock_is_held()` function is called with a `tcp_timewait_sock` object. This occurs because the `tcp_timewait_sock` object lacks the necessary `sk->sk_lock`, leading to an incorrect lockdep annotation. This issue could potentially lead to system instability or other undefined behavior.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64518 https://nvd.nist.gov/vuln/detail/CVE-2026-64518 https://lore.kernel.org/linux-cve-announce/2026072538-CVE-2026-64518-7bc3@gregkh/T