diff --git a/ChangeLog.txt b/ChangeLog.txt
index ded3a8e2..28efef26 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,3 +1,6 @@
+Broker:
+- mosquitto_password now forbids the : character. Closes #1833.
+
 Client library:
 - Fix send quota being incorrecly reset on reconnect. Closes #1822.
 - Don't use logging until log mutex is initialised. Closes #1819.
diff --git a/src/mosquitto_passwd.c b/src/mosquitto_passwd.c
index a86071f9..90f2ff43 100644
--- a/src/mosquitto_passwd.c
+++ b/src/mosquitto_passwd.c
@@ -598,6 +598,10 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 
+	if(strchr(username, ':')){
+		fprintf(stderr, "Error: Username must not contain the ':' character.\n");
+		return 1;
+	}
 #ifdef WIN32
 	password_file = _fullpath(NULL, password_file_tmp, 0);
 	if(!password_file){