diff --git a/src/dwarfs/block_manager.cpp b/src/dwarfs/block_manager.cpp
index 9e38c20a..8b953966 100644
--- a/src/dwarfs/block_manager.cpp
+++ b/src/dwarfs/block_manager.cpp
@@ -396,7 +396,7 @@ class segment_match {
   active_block const* block_;
   uint32_t offset_;
   uint32_t size_{0};
-  uint8_t const* data_;
+  uint8_t const* data_{nullptr};
 };
 
 void active_block::append(uint8_t const* p, size_t size, bloom_filter* filter) {