diff --git a/tv/cec/1.0/default/HdmiCecDefault.cpp b/tv/cec/1.0/default/HdmiCecDefault.cpp
index 26ccb7d..2a5197c 100644
--- a/tv/cec/1.0/default/HdmiCecDefault.cpp
+++ b/tv/cec/1.0/default/HdmiCecDefault.cpp
@@ -278,6 +278,10 @@
 
 Return<bool> HdmiCecDefault::isConnected(int32_t portId) {
     uint16_t addr;
+    if (portId < 0 || portId >= mHdmiCecPorts.size()) {
+        LOG(ERROR) << "Port id is out of bounds, portId = " << portId;
+        return false;
+    }
     int ret = ioctl(mHdmiCecPorts[portId]->mCecFd, CEC_ADAP_G_PHYS_ADDR, &addr);
     if (ret) {
         LOG(ERROR) << "Is connected failed, Error = " << strerror(errno);