--- a/dom/plugins/base/nsPluginTags.cpp
+++ b/dom/plugins/base/nsPluginTags.cpp
@@ -261,16 +261,17 @@ nsPluginTag::nsPluginTag(const char* aNa
                          const char* const* aExtensions,
                          int32_t aVariants,
                          int64_t aLastModifiedTime,
                          bool fromExtension,
                          bool aArgsAreUTF8)
   : nsIInternalPluginTag(aName, aDescription, aFileName, aVersion),
     mId(sNextId++),
     mContentProcessRunningCount(0),
+    mHadLocalInstance(false),
     mLibrary(nullptr),
     mIsJavaPlugin(false),
     mIsFlashPlugin(false),
     mSupportsAsyncInit(false),
     mFullPath(aFullPath),
     mLastModifiedTime(aLastModifiedTime),
     mSandboxLevel(0),
     mCachedBlocklistState(nsIBlocklistService::STATE_NOT_BLOCKED),