hardening

diff --git a/fvwm/misc.c b/fvwm/misc.c
index f303453..16023d0 100644
--- a/fvwm/misc.c
+++ b/fvwm/misc.c
@@ -348,6 +348,7 @@ void fvwm_msg(fvwm_msg_t type, char *id, char *msg, ...)
   va_list args;
 	char fvwm_id[20];
 	char time_str[40] = "\0";
+	char *fmt;
 #ifdef FVWM_DEBUG_TIME
 	clock_t time_val, time_taken;
 	static clock_t start_time = 0;
@@ -388,9 +389,12 @@ void fvwm_msg(fvwm_msg_t type, char *id, char *msg, ...)
 	}
 	else
 	{
+		asprintf(&fmt, "%s", msg);
 		va_start(args, msg);
-		vfprintf(stderr, msg, args);
+		vfprintf(stderr, fmt, args);
 		va_end(args);
+
+		free(fmt);
 	}
 	fprintf(stderr, "\n");
 
diff --git a/libs/FRenderInit.c b/libs/FRenderInit.c
index fcdb259..65bff1a 100644
--- a/libs/FRenderInit.c
+++ b/libs/FRenderInit.c
@@ -129,7 +129,7 @@ Bool FRenderGetErrorText(int code, char *msg)
 		    code <= FRenderErrorBase +
 		    (sizeof(error_names) / sizeof(char *)) -1)
 		{
-			sprintf(msg, error_names[code - FRenderErrorBase]);
+			sprintf(msg, "%s", error_names[code - FRenderErrorBase]);
 			return 1;
 		}
 	}
diff --git a/modules/FvwmIconMan/debug.c b/modules/FvwmIconMan/debug.c
index 9b5c194..9a7afb5 100644
--- a/modules/FvwmIconMan/debug.c
+++ b/modules/FvwmIconMan/debug.c
@@ -38,14 +38,18 @@ void
 ConsoleMessage(const char *fmt, ...)
 {
 	va_list args;
+	char *mfmt;
 
 	assert(console != NULL);
 
 	fputs("FvwmIconMan: ", console);
 
+	asprintf(&mfmt, "%s", fmt);
 	va_start(args, fmt);
-	vfprintf(console, fmt, args);
+	vfprintf(console, mfmt, args);
 	va_end(args);
+
+	free(mfmt);
 }
 
 int