In the Linux kernel, the following vulnerability has been resolved: mptcp: fix NULL pointer dereference on fastopen early fallback In case of early fallback to TCP, subflow_syn_recv_sock() deletes the subflow context before returning the newly allocated sock to the caller. The fastopen path does not cope with the above unconditionally dereferencing the subflow context.
https://git.kernel.org/stable/c/c0ff6f6da66a7791a32c0234388b1bdc00244917
https://git.kernel.org/stable/c/95135835519b0ab931c39908b2c99e9fb3c9068b