diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index 38be934..829958a 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -1309,6 +1309,7 @@
 
 class ImageSource {
   public:
+    virtual ~ImageSource() {};
     virtual bool ReadFile(const std::string& name, std::vector<char>* out) const = 0;
     virtual int OpenFile(const std::string& name) const = 0;
 };