An integer overflow can happen when looping over items in a list.
This can only happen in rare conditions on 32 and 64-bit systems, as the list must contain more than 2,147,483,647 elements.
On 16-bit systems, this happens with a list that contains more than 32,767 elements.
Mitigation
There is no known mitigation.
The upgrade to the latest stable version is highly recommended.
Credit
The issue was discovered by Yiheng Cao.
WSA-2020-3: [IRC] Buffer overflow on new IRC message 005 with nick prefixes.
A buffer overflow happens when a new IRC message 005 is received with longer nick prefixes.
Note: a "normal" IRC server should not send again a message 005 with new nick prefixes, so the problem should be limited to malicious IRC servers.
Mitigation
There is no known mitigation.
The upgrade to the latest stable version is highly recommended.
Date/time conversion specifiers are expanded after replacing buffer local variables in name of log files. In some cases, this can lead to an error in function strftime and a crash caused by the use of an uninitialized buffer.
Mitigation
You can unload the logger plugin, thus stopping recording of all buffers: /plugin unload logger.
Credit
The issue was discovered by Joseph Bisch.
WSA-2017-1: [IRC] Buffer overflow when receiving a DCC file.
Strings are built with uncontrolled format when IRC commands are redirected by relay plugin. If the output or redirected command contains formatting chars like "%", this can lead to a crash of WeeChat.
Mitigation
You can remove all relays of type "irc", see /help relay.
WSA-2013-2: [IRC] Crash on send of unknown commands to IRC server.