The fetchnews NNTP client in leafnode 1.11.2 and earlier can hang while waiting for input that never arrives, which allows remote NNTP servers to cause a denial of service (news loss).
fetchnews in leafnode 1.9.47 and earlier allows remote attackers to cause a denial of service (process hang) via an empty NNTP news article with missing mandatory headers.
The fetchnews NNTP client in leafnode 1.9.3 to 1.9.41 allows remote attackers to cause a denial of service (process hang and termination) via certain malformed Usenet news articles that cause fetchnews to hang while waiting for input.