NULL Pointer Dereference Affecting kernel6.18-libbpf-debuginfo package, versions <1:6.18.15-14.217.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.16% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNEL618LIBBPFDEBUGINFO-17407432
  • published23 Jun 2026
  • disclosed27 May 2026

Introduced: 27 May 2026

CVE-2026-45918  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel6.18-libbpf-debuginfo to version 1:6.18.15-14.217.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1514.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel6.18-libbpf-debuginfo package and not the kernel6.18-libbpf-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

ovpn: tcp - don't deref NULL sk_socket member after tcp_close()

When deleting a peer in case of keepalive expiration, the peer is removed from the OpenVPN hashtable and is temporary inserted in a "release list" for further processing.

This happens in: ovpn_peer_keepalive_work() unlock_ovpn(release_list)

This processing includes detaching from the socket being used to talk to this peer, by restoring its original proto and socket ops/callbacks.

In case of TCP it may happen that, while the peer is sitting in the release list, userspace decides to close the socket. This will result in a concurrent execution of:

tcp_close(sk) __tcp_close(sk) sock_orphan(sk) sk_set_socket(sk, NULL)

The last function call will set sk->sk_socket to NULL.

When the releasing routine is resumed, ovpn_tcp_socket_detach() will attempt to dereference sk->sk_socket to restore its original ops member. This operation will crash due to sk->sk_socket being NULL.

Fix this race condition by testing-and-accessing sk->sk_socket atomically under sk->sk_callback_lock.

CVSS Base Scores

version 3.1