diff --git a/contrib/epee/src/byte_slice.cpp b/contrib/epee/src/byte_slice.cpp
index 72aa397684..7a424383fc 100644
--- a/contrib/epee/src/byte_slice.cpp
+++ b/contrib/epee/src/byte_slice.cpp
@@ -162,7 +162,7 @@ namespace epee
 
       for (const auto& source : sources)
       {
-        std::memcpy(out.data(), source.data(), source.size());
+        std::memcpy(out.data(), source.data(), std::min(out.size(), source.size()));
         if (out.remove_prefix(source.size()) < source.size())
           throw std::bad_alloc{}; // size_t overflow on space_needed
       }