[vbus][rf_bridge][sensirion_common] Add buffer size guards (#14597)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

esphome/components/rf_bridge/rf_bridge.cpp

@@ -145,6 +145,9 @@ void RFBridgeComponent::loop() {
     }
     avail -= to_read;
     for (size_t i = 0; i < to_read; i++) {
+      if (this->rx_buffer_.size() > MAX_RX_BUFFER_SIZE) {
+        this->rx_buffer_.clear();
+      }
       if (this->parse_bridge_byte_(buf[i])) {
         ESP_LOGVV(TAG, "Parsed: 0x%02X", buf[i]);
         this->last_bridge_byte_ = now;

esphome/components/rf_bridge/rf_bridge.h

@@ -30,6 +30,7 @@ static const uint8_t RF_CODE_RFIN_BUCKET = 0xB1;
 static const uint8_t RF_CODE_BEEP = 0xC0;
 static const uint8_t RF_CODE_STOP = 0x55;
 static const uint8_t RF_DEBOUNCE = 200;
+static const size_t MAX_RX_BUFFER_SIZE = 512;
 
 struct RFBridgeData {
   uint16_t sync;

esphome/components/sensirion_common/i2c_sensirion.cpp

@@ -12,7 +12,7 @@ static const char *const TAG = "sensirion_i2c";
 static const size_t BUFFER_STACK_SIZE = 16;
 
 bool SensirionI2CDevice::read_data(uint16_t *data, const uint8_t len) {
-  const uint8_t num_bytes = len * 3;
+  const size_t num_bytes = len * 3;
   uint8_t buf[num_bytes];
 
   this->last_error_ = this->read(buf, num_bytes);

esphome/components/vbus/vbus.cpp

@@ -87,6 +87,9 @@ void VBus::loop() {
           this->state_ = 0;
           ESP_LOGD(TAG, "P1 empty message");
         }
+      } else if (this->buffer_.size() > 15) {
+        ESP_LOGW(TAG, "Unknown protocol 0x%02x, discarding", this->protocol_);
+        this->state_ = 0;
       }
       continue;
     }