Heap-based buffer overflow in WeeChat 0.3.6 through 0.3.9 allows remote attackers to cause a denial of service (crash or hang) and possibly execute arbitrary code via crafted IRC colors that are not properly decoded.

The hookprocess function in the plugin API for WeeChat 0.3.0 through 0.3.9.1 allows remote attackers to execute arbitrary commands via shell metacharacters in a command from a plugin, related to "shell expansion."

logger.c in the logger plugin in WeeChat before 1.9.1 allows a crash via strftime date/time specifiers, because a buffer is not initialized.