anacrolix torrent has unbounded recursion in the bencode decoder that causes stack-overflow crash and CPU-exhaustion DoS
anacrolix/torrent's bencode decoder (bencode/) applies no limit on the nesting depth of nested dictionaries and lists. Two distinct denial-of-service mechanisms follow from that single root cause, both reachable from a single crafted .torrent file or from metadata obtained from a peer on a magnet-link/v2 download: Stack-overflow process crash. Decoder.readOneValue recurses once per nesting level with no depth bound. A .torrent whose info value is a list nested a few million …