diff --git a/src/irc/core/irc-cap.c b/src/irc/core/irc-cap.c
index 2c2df7f9..1c5e1d18 100644
--- a/src/irc/core/irc-cap.c
+++ b/src/irc/core/irc-cap.c
@@ -78,7 +78,16 @@ static void cap_emit_signal (IRC_SERVER_REC *server, char *cmd, char *args)
 {
 	char *signal_name;
 
-	signal_name = g_strdup_printf("server cap %s %s", cmd, args? args: "");
+	if (args == NULL)
+		return;
+
+	/* Cap the number of unique CAP signals emitted per server to prevent
+	 * unbounded signal-name interning from server-controlled CAP tokens. */
+	if (server->cap_supported == NULL ||
+	    g_hash_table_size(server->cap_supported) > 256)
+		return;
+
+	signal_name = g_strdup_printf("server cap %s %s", cmd, args);
 	signal_emit(signal_name, 1, server);
 	g_free(signal_name);
 }
diff --git a/src/irc/dcc/dcc-chat.c b/src/irc/dcc/dcc-chat.c
index 68da0e27..3087649e 100644
--- a/src/irc/dcc/dcc-chat.c
+++ b/src/irc/dcc/dcc-chat.c
@@ -730,6 +730,16 @@ static void dcc_chat_msg(CHAT_DCC_REC *dcc, const char *msg)
 	if (*msg != 1)
 		return;
 
+	/* Cap the CTCP body length that is concatenated into the signal name. The
+	 * body comes from a remote peer on an established DCC CHAT connection
+	 * and is passed as the second argument to any matching signal handler
+	 * (including loaded perl scripts). A modest cap limits the attack surface
+	 * for the dynamic-signal-name dispatch and aligns with the convention
+	 * used for CTCP-over-IRC. */
+	if (strlen(msg+1) > 256) {
+		return;
+	}
+
 	/* get ctcp command, remove \001 chars */
 	event = g_strconcat(reply ? "dcc reply " : "dcc ctcp ", msg+1, NULL);
 	if (event[strlen(event)-1] == 1) event[strlen(event)-1] = '\0';