diff --git a/esphome/components/lvgl/lvgl_esphome.cpp b/esphome/components/lvgl/lvgl_esphome.cpp
index 3e447e9169..66cb25b864 100644
--- a/esphome/components/lvgl/lvgl_esphome.cpp
+++ b/esphome/components/lvgl/lvgl_esphome.cpp
@@ -422,6 +422,9 @@ void LvglComponent::write_random_() {
     auto row = random_uint32() % this->disp_drv_.ver_res;
     row = row / this->draw_rounding * this->draw_rounding;
     auto size = ((random_uint32() % 32) / this->draw_rounding + 2) * this->draw_rounding - 1;
+    // clamp size so the square fits within the draw buffer
+    if ((size + 1) * (size + 1) > this->draw_buf_.size)
+      size = static_cast<decltype(size)>(sqrtf(this->draw_buf_.size)) - 1;
     lv_area_t area;
     area.x1 = col;
     area.y1 = row;
diff --git a/esphome/components/packet_transport/packet_transport.cpp b/esphome/components/packet_transport/packet_transport.cpp
index 6f1286b469..964037a02c 100644
--- a/esphome/components/packet_transport/packet_transport.cpp
+++ b/esphome/components/packet_transport/packet_transport.cpp
@@ -137,6 +137,8 @@ class PacketDecoder {
       return DECODE_EMPTY;
     if (this->buffer_[this->position_] != key)
       return DECODE_UNMATCHED;
+    if (this->position_ + 1 + sizeof(T) > this->len_)
+      return DECODE_ERROR;
     this->position_++;
     T value = 0;
     for (size_t i = 0; i != sizeof(T); ++i) {
diff --git a/esphome/components/seeed_mr60fda2/seeed_mr60fda2.cpp b/esphome/components/seeed_mr60fda2/seeed_mr60fda2.cpp
index 5d571618d3..c6527a948e 100644
--- a/esphome/components/seeed_mr60fda2/seeed_mr60fda2.cpp
+++ b/esphome/components/seeed_mr60fda2/seeed_mr60fda2.cpp
@@ -149,28 +149,25 @@ void MR60FDA2Component::split_frame_(uint8_t buffer) {
   switch (this->current_frame_locate_) {
     case LOCATE_FRAME_HEADER:  // starting buffer
       if (buffer == FRAME_HEADER_BUFFER) {
-        this->current_frame_len_ = 1;
-        this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+        this->current_frame_len_ = 0;
+        this->current_frame_buf_[this->current_frame_len_++] = buffer;
         this->current_frame_locate_++;
       }
       break;
     case LOCATE_ID_FRAME1:
       this->current_frame_id_ = buffer << 8;
-      this->current_frame_len_++;
-      this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+      this->current_frame_buf_[this->current_frame_len_++] = buffer;
       this->current_frame_locate_++;
       break;
     case LOCATE_ID_FRAME2:
       this->current_frame_id_ += buffer;
-      this->current_frame_len_++;
-      this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+      this->current_frame_buf_[this->current_frame_len_++] = buffer;
       this->current_frame_locate_++;
       break;
     case LOCATE_LENGTH_FRAME_H:
       this->current_data_frame_len_ = buffer << 8;
-      if (this->current_data_frame_len_ == 0x00) {
-        this->current_frame_len_++;
-        this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+      if (this->current_data_frame_len_ == 0) {
+        this->current_frame_buf_[this->current_frame_len_++] = buffer;
         this->current_frame_locate_++;
       } else {
         this->current_frame_locate_ = LOCATE_FRAME_HEADER;
@@ -181,15 +178,13 @@ void MR60FDA2Component::split_frame_(uint8_t buffer) {
       if (this->current_data_frame_len_ > DATA_BUF_MAX_SIZE) {
         this->current_frame_locate_ = LOCATE_FRAME_HEADER;
       } else {
-        this->current_frame_len_++;
-        this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+        this->current_frame_buf_[this->current_frame_len_++] = buffer;
         this->current_frame_locate_++;
       }
       break;
     case LOCATE_TYPE_FRAME1:
       this->current_frame_type_ = buffer << 8;
-      this->current_frame_len_++;
-      this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+      this->current_frame_buf_[this->current_frame_len_++] = buffer;
       this->current_frame_locate_++;
       break;
     case LOCATE_TYPE_FRAME2:
@@ -198,8 +193,7 @@ void MR60FDA2Component::split_frame_(uint8_t buffer) {
           (this->current_frame_type_ == PEOPLE_EXIST_TYPE_BUFFER) ||
           (this->current_frame_type_ == RESULT_INSTALL_HEIGHT) || (this->current_frame_type_ == RESULT_PARAMETERS) ||
           (this->current_frame_type_ == RESULT_HEIGHT_THRESHOLD) || (this->current_frame_type_ == RESULT_SENSITIVITY)) {
-        this->current_frame_len_++;
-        this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+        this->current_frame_buf_[this->current_frame_len_++] = buffer;
         this->current_frame_locate_++;
       } else {
         this->current_frame_locate_ = LOCATE_FRAME_HEADER;
@@ -207,8 +201,7 @@ void MR60FDA2Component::split_frame_(uint8_t buffer) {
       break;
     case LOCATE_HEAD_CKSUM_FRAME:
       if (validate_checksum(this->current_frame_buf_, this->current_frame_len_, buffer)) {
-        this->current_frame_len_++;
-        this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+        this->current_frame_buf_[this->current_frame_len_++] = buffer;
         this->current_frame_locate_++;
       } else {
         ESP_LOGD(TAG, "HEAD_CKSUM_FRAME ERROR: 0x%02x", buffer);
@@ -223,21 +216,20 @@ void MR60FDA2Component::split_frame_(uint8_t buffer) {
       }
       break;
     case LOCATE_DATA_FRAME:
-      this->current_frame_len_++;
-      this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
-      this->current_data_buf_[this->current_frame_len_ - LEN_TO_DATA_FRAME] = buffer;
-      if (this->current_frame_len_ - LEN_TO_HEAD_CKSUM == this->current_data_frame_len_) {
-        this->current_frame_locate_++;
-      }
-      if (this->current_frame_len_ > FRAME_BUF_MAX_SIZE) {
+      if (this->current_frame_len_ >= FRAME_BUF_MAX_SIZE) {
         ESP_LOGD(TAG, "PRACTICE_DATA_FRAME_LEN ERROR: %d", this->current_frame_len_ - LEN_TO_HEAD_CKSUM);
         this->current_frame_locate_ = LOCATE_FRAME_HEADER;
+        break;
+      }
+      this->current_data_buf_[this->current_frame_len_ - LEN_TO_DATA_FRAME + 1] = buffer;
+      this->current_frame_buf_[this->current_frame_len_++] = buffer;
+      if (this->current_frame_len_ - LEN_TO_HEAD_CKSUM == this->current_data_frame_len_) {
+        this->current_frame_locate_++;
       }
       break;
     case LOCATE_DATA_CKSUM_FRAME:
       if (validate_checksum(this->current_data_buf_, this->current_data_frame_len_, buffer)) {
-        this->current_frame_len_++;
-        this->current_frame_buf_[this->current_frame_len_ - 1] = buffer;
+        this->current_frame_buf_[this->current_frame_len_++] = buffer;
         this->current_frame_locate_++;
         this->process_frame_();
       } else {
diff --git a/esphome/components/shelly_dimmer/shelly_dimmer.cpp b/esphome/components/shelly_dimmer/shelly_dimmer.cpp
index bdb33d31af..88fcbcbfe1 100644
--- a/esphome/components/shelly_dimmer/shelly_dimmer.cpp
+++ b/esphome/components/shelly_dimmer/shelly_dimmer.cpp
@@ -188,8 +188,8 @@ bool ShellyDimmer::upgrade_firmware_() {
       break;
     }
 
-    std::memcpy(buffer, p, BUFFER_SIZE);
-    p += BUFFER_SIZE;
+    std::memcpy(buffer, p, len);
+    p += len;
 
     if (stm32_write_memory(stm32, addr, buffer, len) != STM32_ERR_OK) {
       ESP_LOGW(TAG, "Failed to write to STM32 flash memory");