An issue was discovered in net/ipv4/sysctlnetipv4.c in the Linux kernel before 5.0.11. There is a net/ipv4/tcpinput.c signed integer overflow in tcpackupdatertt() when userspace writes a very large integer to /proc/sys/net/ipv4/tcpminrtt_wlen, leading to a denial of service or possibly unspecified other impact, aka CID-19fad20d15a6.