tcp_emu in tcp_subr.c in libslirp 4.1.0, as used in QEMU 4.2.0, mismanages memory, as demonstrated by IRC DCC commands in EMU_IRC. This can cause a heap-based buffer overflow or other out-of-bounds access which can lead to a DoS or potential execute arbitrary code. CREATE(Triage):(User=admin) CVE-2020-7039 (https://nvd.nist.gov/vuln/detail/CVE-2020-7039)