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

sock_map: fix a NULL pointer dereference in sock_map_link_update_prog()

The following race condition could trigger a NULL pointer dereference:

sock_map_link_detach(): sock_map_link_update_prog():
mutex_lock(&sockmap_mutex);
...
sockmap_link->map = NULL;
mutex_unlock(&sockmap_mutex);
mutex_lock(&sockmap_mutex);
...
sock_map_prog_link_lookup(sockmap_link->map);
mutex_unlock(&sockmap_mutex);

Fix it by adding a NULL pointer check. In this specific case, it makes
no sense to update a link which is being released.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-50260
• https://git.kernel.org/stable/c/740be3b9a6d73336f8c7d540842d0831dc7a808b
• https://git.kernel.org/stable/c/9afe35fdda16e09d5bd3c49a68ba8c680dd678bd