Fetchmail 6.2.4 and earlier does not properly allocate memory for long lines, which allows remote attackers to cause a denial of service (crash) via a certain email.
Heap-based buffer overflow in Fetchmail 6.1.3 and earlier does not account for the "@" character when determining buffer lengths for local addresses, which allows remote attackers to execute arbitrary code via a header with a large number of local addresses.
Buffer overflows in Fetchmail 6.0.0 and earlier allow remote attackers to cause a denial of service (crash) or execute arbitrary code via (1) long headers that are not properly processed by the readheaders function, or (2) via long Received: headers, which are not properly parsed by the parse_received function.
The getmxrecord function in Fetchmail 6.0.0 and earlier does not properly check the boundary of a particular malformed DNS packet from a malicious DNS server, which allows remote attackers to cause a denial of service (crash) when Fetchmail attempts to read data beyond the expected boundary.