diff --git a/legacy/firmware/layout2.c b/legacy/firmware/layout2.c
index 7802ece2c..e482a80e3 100644
--- a/legacy/firmware/layout2.c
+++ b/legacy/firmware/layout2.c
@@ -574,6 +574,7 @@ void layoutAddress(const char *address, const char *desc, bool qrcode,
   uint32_t addrlen = strlen(address);
   if (qrcode) {
     char address_upcase[addrlen + 1];
+    memset(address_upcase, 0, sizeof(address_upcase));
     if (ignorecase) {
       for (uint32_t i = 0; i < addrlen + 1; i++) {
         address_upcase[i] = address[i] >= 'a' && address[i] <= 'z'
diff --git a/legacy/firmware/nem2.c b/legacy/firmware/nem2.c
index 74271765a..102808c40 100644
--- a/legacy/firmware/nem2.c
+++ b/legacy/firmware/nem2.c
@@ -210,6 +210,7 @@ bool nem_askTransfer(const NEMTransactionCommon *common,
     bool unknownMosaic = false;
 
     const NEMMosaicDefinition *definitions[transfer->mosaics_count];
+    memset(definitions, 0, sizeof(definitions));
 
     for (size_t i = 0; i < transfer->mosaics_count; i++) {
       const NEMMosaic *mosaic = &transfer->mosaics[i];
diff --git a/legacy/firmware/stellar.c b/legacy/firmware/stellar.c
index ccfd794f4..3607104f7 100644
--- a/legacy/firmware/stellar.c
+++ b/legacy/firmware/stellar.c
@@ -1339,6 +1339,8 @@ size_t stellar_publicAddressAsStr(const uint8_t *bytes, char *out,
   // version + key bytes + checksum
   uint8_t keylen = 1 + 32 + 2;
   uint8_t bytes_full[keylen];
+  memset(bytes_full, 0, sizeof(bytes_full));
+
   bytes_full[0] = 6 << 3;  // 'G'
 
   memcpy(bytes_full + 1, bytes, 32);