In the Linux kernel, the following vulnerability has been resolved: net: Fix TOCTOU issue in sk_is_readable() sk->sk_prot->sock_is_readable is a valid function pointer when sk resides in a sockmap. After the last sk_psock_put() (which usually happens when socket is removed from sockmap), sk->sk_prot gets restored and sk->sk_prot->sock_is_readable becomes NULL. This makes sk_is_readable() racy, if the value of sk->sk_prot is reloaded after the initial check. Which in turn may lead to a null pointer dereference. Ensure the function pointer does not turn NULL after the check.
5.3.0-18.195.3.0-24.265.4.0-100.1135.4.0-104.1185.4.0-105.1195.4.0-107.1215.4.0-109.1235.4.0-110.1245.4.0-113.1275.4.0-117.132+109 more4.13.0-16.196.11.0-8.86.12.0-12.126.12.0-15.156.12.0-16.166.14.0-10.106.14.0-11.116.14.0-13.136.14.0-15.156.14.0-22.226.14.0-23.23+1 more4.2.0-16.194.2.0-17.214.2.0-19.234.3.0-1.104.3.0-2.114.3.0-5.164.3.0-6.174.3.0-7.184.4.0-2.163.11.0-12.195.13.0-19.195.15.0-100.1105.15.0-101.1115.15.0-102.1125.15.0-105.1155.15.0-106.1165.15.0-107.1175.15.0-112.1225.15.0-113.1235.15.0-116.126+67 more6.5.0-9.96.6.0-14.146.8.0-11.116.8.0-20.206.8.0-22.226.8.0-28.286.8.0-31.316.8.0-35.356.8.0-36.366.8.0-38.38+21 more5.19.0-1007.7~22.04.15.19.0-1009.9~22.04.15.19.0-1010.10~22.04.15.19.0-1011.11~22.04.15.19.0-1012.12~22.04.15.19.0-1013.13~22.04.15.19.0-1014.14~22.04.15.19.0-1015.15~22.04.15.13.0-1005.65.15.0-1002.45.15.0-1003.55.15.0-1004.65.15.0-1005.75.15.0-1008.105.15.0-1009.115.15.0-1011.145.15.0-1013.175.15.0-1014.18+59 more6.5.0-1008.86.6.0-1001.16.8.0-1001.16.8.0-1006.66.8.0-1008.86.8.0-1009.96.8.0-1010.106.8.0-1011.126.8.0-1012.136.8.0-1013.14+17 more