Resource Management Errors
fetchmail 5.9.9 through 6.3.19 does not properly limit the wait time after issuing a (1) STARTTLS or (2) STLS request, which allows remote servers to cause a denial of service (application hang) by acknowledging the request but not sending additional packets.
CWE-399 - Resource Management Errors
Resource management errors is not a weakness in and of itself, rather it is a category of weaknesses related to improper management of system resources. If not addressed, the weaknesses in this category can lead to unexpected software behavior, loss of access, file modification, sensitive information disclosure, system crash, denial of service, and code execution.