diff --git a/gcore/overview.cpp b/gcore/overview.cpp
index 8d1c4f3b2444..bd53d67fc73e 100644
--- a/gcore/overview.cpp
+++ b/gcore/overview.cpp
@@ -3142,7 +3142,10 @@ static CPLErr GDALResampleChunk_ConvolutionT(
                    : dfNoDataValue;
     // cppcheck-suppress unreadVariable
     const int isIntegerDT = GDALDataTypeIsInteger(dstDataType);
-    const auto nNodataValueInt64 = static_cast<GInt64>(dfNoDataValue);
+    const auto nNodataValueInt64 =
+        isIntegerDT && GDALIsValueExactAs<GInt64>(dfNoDataValue)
+            ? static_cast<GInt64>(dfNoDataValue)
+            : 0;
     constexpr int nWrkDataTypeSize = static_cast<int>(sizeof(Twork));
 
     // TODO: we should have some generic function to do this.