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).
lists.opensuse.org/opensuse-security-announce/2020-02/msg00032.html
github.com/weechat/weechat/commit/6f4f147d8e86adf9ad34a8ffd7e7f1f23a7e74da
lists.debian.org/debian-lts-announce/2020/03/msg00031.html
lists.debian.org/debian-lts-announce/2021/09/msg00018.html
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ASRTCQFFDAAK347URWNDH6NSED2BGNY/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ER23GT23US5JXDLUZAMGMWXKZ74MI4S2/
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M3LAJTLI3LWZRNCFYJ7PCBBTHUMCCBHH/
security.gentoo.org/glsa/202003-51
weechat.org/doc/security/