diff --git a/source/backend/qnn/backend/QNNBackend.cpp b/source/backend/qnn/backend/QNNBackend.cpp
index 7dcae6d583..d41997535e 100644
--- a/source/backend/qnn/backend/QNNBackend.cpp
+++ b/source/backend/qnn/backend/QNNBackend.cpp
@@ -2432,9 +2432,19 @@ class QnnRuntimeCreator : public RuntimeCreator {
                 }
                 if (op->main_as_Convolution2D() && op->main_as_Convolution2D()->weight() != nullptr) {
                     return false;
-                } else {
-                    return true;
                 }
+                // Guard against promoting a Conv that carries no quantized weight
+                // data (e.g. a Conv listed in skip_quant_op_names but still
+                // surrounded by int8 tensors): the QNN Conv execution would later
+                // dereference a missing weight and crash.
+                {
+                    auto conv2d = op->main_as_Convolution2D();
+                    if (conv2d->quanParameter() == nullptr &&
+                        (conv2d->symmetricQuan() == nullptr || conv2d->symmetricQuan()->weight() == nullptr)) {
+                        return false;
+                    }
+                }
+                return true;
             case OpType_ReLU:
                 if ((op->main_as_Relu() == nullptr) || op->main_as_Relu()->slope() == 0.f) {
                     return true;
diff --git a/source/backend/qnn/execution/QNNConvDepthwise.cpp b/source/backend/qnn/execution/QNNConvDepthwise.cpp
index 45124a3d7b..7839c4c2a3 100644
--- a/source/backend/qnn/execution/QNNConvDepthwise.cpp
+++ b/source/backend/qnn/execution/QNNConvDepthwise.cpp
@@ -29,7 +29,7 @@ void QNNConvDepthwise::isWeightQuantSupported(const Tensor *input, const int oc)
         }
         
         std::shared_ptr<ConvolutionCommon::Int8Common> quanCommon = ConvolutionCommon::load(mOp, this->backend(), false, true);
-        if(quanCommon->asymmetric || dataType == QNN_DATATYPE_FLOAT_16 || dataType == QNN_DATATYPE_FLOAT_32){
+        if (nullptr == quanCommon || quanCommon->asymmetric || dataType == QNN_DATATYPE_FLOAT_16 || dataType == QNN_DATATYPE_FLOAT_32) {
             // not support asymmetric and mBlockSize > 1 results incorrect now
             mWeightQuant = false;
             return;
@@ -194,7 +194,9 @@ ErrorCode QNNConvDepthwise::onEncode(const std::vector<Tensor *> &inputs, const
     this->createParamTensor("pad_amount", QNN_DATATYPE_UINT_32, {2, 2}, (void *)padAmountData.data());
     this->createParamTensor("dilation", QNN_DATATYPE_UINT_32, {2}, (void *)dilationData.data());
 
-    this->createWeightAndBias(dataType, inputs[0], oc, kernelH, kernelW);
+    if (!this->createWeightAndBias(dataType, inputs[0], oc, kernelH, kernelW)) {
+        return NOT_SUPPORT;
+    }
     // dequant input and quant output
     if(mWeightQuant == false && dataType != QNN_DATATYPE_FLOAT_16 && dataType != QNN_DATATYPE_FLOAT_32){
         return this->onEncodeQuantDequantDepthConv(inputs[0], outputs[0], n, ic, oc);
@@ -261,6 +263,11 @@ void QNNConvDepthwise::createWeightAndBias(Qnn_DataType_t dataType, const Tensor
     if(mWeightQuant){
         Qnn_QuantizeParams_t weightQuantize{};
         std::shared_ptr<ConvolutionCommon::Int8Common> quanCommon = ConvolutionCommon::load(mOp, this->backend(), false, true);
+        if (nullptr == quanCommon) {
+            MNN_ERROR("QNNConvDepthwise: op '%s' has no quantized weight data\n",
+                      mOp->name() ? mOp->name()->c_str() : "unknown");
+            return;
+        }
 
         // [TODO] Support asymmetric and other quantBits.
         MNN_ASSERT(!quanCommon->asymmetric);
@@ -376,6 +383,11 @@ void QNNConvDepthwise::createWeightAndBias(Qnn_DataType_t dataType, const Tensor
         int weightElementNum = 0;
         std::shared_ptr<ConvolutionCommon::Int8Common> quanWeight;
         ConvolutionCommon::getConvParameters(&quanWeight, mBackend, mOp, &source, &weightElementNum);
+        if (nullptr == source || weightElementNum <= 0) {
+            MNN_ERROR("QNNConvDepthwise: op '%s' has no weight data\n",
+                      mOp->name() ? mOp->name()->c_str() : "unknown");
+            return;
+        }
         // oc ic h w ---> h w ic oc
         weightData.resize(weightElementNum);
         convertWeight(source, (float *) weightData.data(), oc, kernelH, kernelW);
diff --git a/source/backend/qnn/execution/QNNConvolution.cpp b/source/backend/qnn/execution/QNNConvolution.cpp
index ae3ca145ab..a65b490037 100644
--- a/source/backend/qnn/execution/QNNConvolution.cpp
+++ b/source/backend/qnn/execution/QNNConvolution.cpp
@@ -41,6 +41,10 @@ void QNNConvolution::isWeightQuantSupported(const Tensor *input, const int ic, c
         }
         
         std::shared_ptr<ConvolutionCommon::Int8Common> quanCommon = ConvolutionCommon::load(mOp, this->backend(), false, true);
+        if (nullptr == quanCommon) {
+            mWeightQuant = false;
+            return;
+        }
         int totalCount = quanCommon->alpha.size();
         mBlockSize = totalCount / oc;
         if(quanCommon->asymmetric){
@@ -118,7 +122,9 @@ ErrorCode QNNConvolution::onEncode(const std::vector<Tensor *> &inputs, const st
         this->createParamScalar("group", (uint32_t)group);
     }
 
-    this->createWeightAndBias(dataType, inputs[0], oc, ic, kernelH, kernelW, group);
+    if (!this->createWeightAndBias(dataType, inputs[0], oc, ic, kernelH, kernelW, group)) {
+        return NOT_SUPPORT;
+    }
     // dequant input and quant output
     if(mWeightQuant == false && dataType != QNN_DATATYPE_FLOAT_16 && dataType != QNN_DATATYPE_FLOAT_32){
         return this->onEncodeQuantDequantConv(inputs[0], outputs[0], n, ic, oc);
@@ -562,6 +568,11 @@ bool QNNConvolution::createWeightAndBias(Qnn_DataType_t dataType, const Tensor *
     if(mWeightQuant){
         Qnn_QuantizeParams_t weightQuantize{};
         std::shared_ptr<ConvolutionCommon::Int8Common> quanCommon = ConvolutionCommon::load(mOp, this->backend(), false, true);
+        if (nullptr == quanCommon) {
+            MNN_ERROR("QNNConvolution: op '%s' has no quantized weight data\n",
+                      mOp->name() ? mOp->name()->c_str() : "unknown");
+            return false;
+        }
         if(quanCommon->asymmetric) {
             MNN_ERROR("[Error]: Qnn weight quant only support symmetric currently\n");
             return false;
@@ -676,6 +687,11 @@ bool QNNConvolution::createWeightAndBias(Qnn_DataType_t dataType, const Tensor *
         int weightElementNum = 0;
         std::shared_ptr<ConvolutionCommon::Int8Common> quanWeight;
         ConvolutionCommon::getConvParameters(&quanWeight, mBackend, mOp, &source, &weightElementNum);
+        if (nullptr == source || weightElementNum <= 0) {
+            MNN_ERROR("QNNConvolution: op '%s' has no weight data\n",
+                      mOp->name() ? mOp->name()->c_str() : "unknown");
+            return false;
+        }
         // oc ic h w ---> h w ic oc
         weightData.resize(weightElementNum);
         convertWeight(source, (float *) weightData.data(), oc, ic/group, kernelH, kernelW);