Please be advised, that it is strongly recommended to upgrade to
version 2.10.3p5, not only apply that patch. Thank you.

--- ../../cvs/irc2.10.3/ircd/channel.c	Fri Oct 10 22:34:05 2003
+++ channel.c	Sat Oct 11 00:03:40 2003
@@ -2001,7 +2001,7 @@
 	Reg	Link	*lp;
 	Reg	aChannel *chptr;
 	Reg	char	*name, *key = NULL;
-	int	i, flags = 0;
+	int	i, tmplen, flags = 0;
 	char	*p = NULL, *p2 = NULL, *s, chop[5];
 
 	if (parc < 2 || *parv[1] == '\0')
@@ -2150,10 +2150,20 @@
 					   parv[0]), name);
 			continue;
 		    }
+		tmplen = strlen(name);
+		if (i + tmplen + 2 /* comma and \0 */
+			>= sizeof(jbuf) )
+		{
+
+			break;
+
+		}
 		if (*jbuf)
-			(void)strcat(jbuf, ",");
-		(void)strncat(jbuf, name, sizeof(jbuf) - i - 1);
-		i += strlen(name)+1;
+		{
+			jbuf[i++] = ',';
+		}
+		(void)strcpy(jbuf + i, name);
+		i += tmplen;
 	    }
 
 	p = NULL;
@@ -2305,6 +2315,16 @@
 					   parv[0], name, chop);
 		else if (*chptr->chname != '&')
 		    {
+			/* ":" (1) "nick" (NICKLEN) " JOIN :" (7), comma (1)
+			** possible chop (4), ending \r\n\0 (3) = 16
+			** must fit in the cbuf as well! --B. */
+			if (strlen(cbuf) + strlen(name) + NICKLEN + 16
+				 >= sizeof(cbuf))
+			{
+				sendto_serv_butone(cptr, ":%s JOIN :%s",
+					parv[0], cbuf);
+				cbuf[0] = '\0';
+			}
 			if (*cbuf)
 				strcat(cbuf, ",");
 			strcat(cbuf, name);