diff --git a/src/workers/Hashrate.cpp b/src/workers/Hashrate.cpp
index 7d2e6a4c5..71aa9cc66 100644
--- a/src/workers/Hashrate.cpp
+++ b/src/workers/Hashrate.cpp
@@ -151,10 +151,10 @@ void Hashrate::add(size_t threadId, uint64_t count, uint64_t timestamp)
 
 void Hashrate::print()
 {
-    char num1[8];
-    char num2[8];
-    char num3[8];
-    char num4[8];
+    char num1[8] = { 0 };
+    char num2[8] = { 0 };
+    char num3[8] = { 0 };
+    char num4[8] = { 0 };
 
     LOG_INFO(m_controller->config()->isColors() ? "\x1B[01;37mspeed\x1B[0m 2.5s/60s/15m \x1B[01;36m%s \x1B[22;36m%s %s \x1B[01;36mH/s\x1B[0m max: \x1B[01;36m%s H/s" : "speed 2.5s/60s/15m %s %s %s H/s max: %s H/s",
              format(calc(ShortInterval),  num1, sizeof(num1)),