diff --git a/CMakeLists.txt b/CMakeLists.txt
index be41ba4..01e0d0d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -264,6 +264,13 @@ if(BUILD_SHARED_LIBS)
   )
 endif(BUILD_SHARED_LIBS)
 
+check_cxx_compiler_flag(-Werror=conditional-uninitialized HAVE_CONDITIONAL_UNINITIALIZED)
+if(HAVE_CONDITIONAL_UNINITIALIZED)
+  target_compile_options(leveldb
+    PUBLIC
+      -Werror=conditional-uninitialized)
+endif(HAVE_CONDITIONAL_UNINITIALIZED)
+
 if(HAVE_CLANG_THREAD_SAFETY)
   target_compile_options(leveldb
     PUBLIC
diff --git a/db/corruption_test.cc b/db/corruption_test.cc
index b22f9e7..4fdbfad 100644
--- a/db/corruption_test.cc
+++ b/db/corruption_test.cc
@@ -157,7 +157,7 @@ class CorruptionTest : public testing::Test {
 
   int Property(const std::string& name) {
     std::string property;
-    int result;
+    int result = -1;
     if (db_->GetProperty(name, &property) &&
         sscanf(property.c_str(), "%d", &result) == 1) {
       return result;
diff --git a/db/version_set.cc b/db/version_set.cc
index 2d5e51a..1824e87 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -994,7 +994,7 @@ bool VersionSet::ReuseManifest(const std::string& dscname,
   }
   FileType manifest_type;
   uint64_t manifest_number;
-  uint64_t manifest_size;
+  uint64_t manifest_size = 0;
   if (!ParseFileName(dscbase, &manifest_number, &manifest_type) ||
       manifest_type != kDescriptorFile ||
       !env_->GetFileSize(dscname, &manifest_size).ok() ||