From 79d50837c91ffe5920f4e3c0f2b380169a7b2a2f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Helleu?= <flashcode@flashtux.org>
Date: Tue, 3 Aug 2021 20:01:15 +0200
Subject: [PATCH] irc: fix read out of bounds in case of malformed AUTHENTICATE
 message (issue #1679)

---
 src/plugins/irc/irc-protocol.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/plugins/irc/irc-protocol.c b/src/plugins/irc/irc-protocol.c
index 9eb6e8de5..70a78348f 100644
--- a/src/plugins/irc/irc-protocol.c
+++ b/src/plugins/irc/irc-protocol.c
@@ -408,6 +408,8 @@ IRC_PROTOCOL_CALLBACK(authenticate)
         return WEECHAT_RC_OK;
 
     arg_data = (argv[0][0] == ':') ? 2 : 1;
+    if (arg_data >= argc)
+        return WEECHAT_RC_OK;
     ptr_data = (argv_eol[arg_data][0] == ':') ?
         argv_eol[arg_data] + 1 : argv_eol[arg_data];