CVE-2026-45918 Details
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.
A vulnerability in the Linux kernel's OpenVPN implementation for TCP can lead to a null pointer dereference. This issue arises when a peer is removed from the OpenVPN hashtable due to keepalive expiration and temporarily placed in a release list. While in this release list, if the userspace closes the associated socket, it triggers a race condition. The socket's sk_socket member can be set to NULL, and when the release process resumes, it attempts to access the now-null sk_socket to restore the original socket operations. This results in a crash. The vulnerability affects the Linux kernel stable tree.
The vulnerability has been addressed by modifying the OpenVPN TCP socket detachment process to access the sk_socket member atomically under the sk_callback_lock, preventing it from being set to NULL while still in use.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/94560267d6c41b1ff3fafbab726e3f8a55a6af34 | kernel.org | Patch |
| https://git.kernel.org/stable/c/b9142cf4e066c825ec68752a7dcaceda700bbe26 | kernel.org | Patch |
| https://git.kernel.org/stable/c/f998b2c4bec487063a586695159f9a1856e81c56 | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-476 | NULL Pointer Dereference | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 6.16, < 6.18.14 >= 6.19, < 6.19.4 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 24, 2026 | Initial Analysis | [email protected] |
| Jun 17, 2026 | CVE Modified | kernel.org |
| May 27, 2026 | New CVE Received | kernel.org |