diff --git a/src/corelib/io/qzip.cpp b/src/corelib/io/qzip.cpp
index 1e3d5f5859e..12224ff4d33 100644
--- a/src/corelib/io/qzip.cpp
+++ b/src/corelib/io/qzip.cpp
@@ -91,7 +91,7 @@ static void writeMSDosDate(uchar *dest, const QDateTime& dt)
 
 static int inflate(Bytef *dest, ulong *destLen, const Bytef *source, ulong sourceLen)
 {
-    z_stream stream;
+    z_stream stream = {};
     int err;
 
     stream.next_in = const_cast<Bytef*>(source);
@@ -104,9 +104,6 @@ static int inflate(Bytef *dest, ulong *destLen, const Bytef *source, ulong sourc
     if ((uLong)stream.avail_out != *destLen)
         return Z_BUF_ERROR;
 
-    stream.zalloc = (alloc_func)nullptr;
-    stream.zfree = (free_func)nullptr;
-
     err = inflateInit2(&stream, -MAX_WBITS);
     if (err != Z_OK)
         return err;