WeeChat before 4.4.2 has an integer overflow and resultant buffer overflow at core/core-string.c when there are more than two billion items in a list. This affects string_free_split_shared , string_free_split, string_free_split_command, and string_free_split_tags.

WeeChat (aka Wee Enhanced Environment for Chat) 3.2 to 3.4 before 3.4.1 does not properly verify the TLS certificate of the server, after certain GnuTLS options are changed, which allows man-in-the-middle attackers to spoof a TLS chat server via an arbitrary certificate. NOTE: this only affects situations where weechat.network.gnutls_ca_system or weechat.network.gnutls_ca_user is changed without a WeeChat restart.

WeeChat before 3.2.1 allows remote attackers to cause a denial of service (crash) via a crafted WebSocket frame that trigger an out-of-bounds read in plugins/relay/relay-websocket.c in the Relay plugin.

An issue was discovered in WeeChat before 2.7.1 (0.3.4 to 2.7 are affected). When a new IRC message 005 is received with longer nick prefixes, a buffer overflow and possibly a crash can happen when a new mode is set for a nick.

irc_mode_channel_update in plugins/irc/irc-mode.c in WeeChat through 2.7 allows remote attackers to cause a denial of service (buffer overflow and application crash) or possibly have unspecified other impact via a malformed IRC message 324 (channel mode).

WeeChat before 1.7.1 allows a remote crash by sending a filename via DCC to the IRC plugin. This occurs in the irc_ctcp_dcc_filename_without_quotes function during quote removal, with a buffer overflow.

The hook_process 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."

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.

Wee Enhanced Environment for Chat (aka WeeChat) 0.3.4 and earlier does not properly verify that the server hostname matches the domain name of the subject of an X.509 certificate, which allows man-in-the-middle attackers to spoof an SSL chat server via an arbitrary certificate, related to incorrect use of the GnuTLS API.

Wee Enhanced Environment for Chat (WeeChat) 0.2.6 allows remote attackers to cause a denial of service (crash) via an IRC PRIVMSG command containing crafted color codes that trigger an out-of-bounds read.