# CVE-2026-45918: linux: In the Linux kernel, the following vulnerability has been resolved: ovpn: tcp - don't deref NULL sk_socket member af... CVE-2026-45918 is fixed in 23 products on 1 platform, first by ALAS2023-2026-1514, released March 30, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-45918 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0016 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Mar 30, 2026 ## Description 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel-livepatch-6.18.15-14.217 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-libbpf amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-libbpf-debuginfo amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-libbpf-devel amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-libbpf-static amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | linux Debian 14 | 6.18.14-1 | [DEBIAN-CVE-2026-45918](https://patchblox.com/security/data/fix/linux/debian-cve-2026-45918.md) | May 27, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.15-14.217.amzn2023 | [ALAS2023-2026-1514](https://patchblox.com/security/data/fix/linux/alas2023-2026-1514.md) | Mar 30, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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