The STARTTLS implementation in nnrpd in INN before 2.5.3 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack, a similar issue to CVE-2011-0411.
Buffer overflow in the ARTpost function in art.c in the control message handling code for INN 2.4.0 may allow remote attackers to execute arbitrary code.
Format string vulnerabilities in (1) inews or (2) rnews for INN 2.2.3 and earlier allow local users and remote malicious NNTP servers to gain privileges via format string specifiers in NTTP responses.
Buffer overflow in innfeed for ISC InterNetNews (INN) before 2.3.0 allows local users in the "news" group to gain privileges via a long -c command line argument.
The INN inndstart program allows local users to gain privileges by specifying an alternate configuration file using the INNCONF environmental variable.