diff --git a/.words b/.words
index 7e36e7d257f..c112c532453 100644
--- a/.words
+++ b/.words
@@ -46,6 +46,7 @@ mutex
 prefetching
 protobuf
 prometheus
+racey
 rafthttp
 repin
 rpc
diff --git a/clientv3/ctx.go b/clientv3/ctx.go
index 869b0fa6911..012eefbdc0c 100644
--- a/clientv3/ctx.go
+++ b/clientv3/ctx.go
@@ -30,9 +30,10 @@ func WithRequireLeader(ctx context.Context) context.Context {
 		md = metadata.Pairs(rpctypes.MetadataRequireLeaderKey, rpctypes.MetadataHasLeader)
 		return metadata.NewOutgoingContext(ctx, md)
 	}
+	copied := md.Copy() // avoid racey updates
 	// overwrite/add 'hasleader' key/value
-	md.Set(rpctypes.MetadataRequireLeaderKey, rpctypes.MetadataHasLeader)
-	return metadata.NewOutgoingContext(ctx, md)
+	copied.Set(rpctypes.MetadataRequireLeaderKey, rpctypes.MetadataHasLeader)
+	return metadata.NewOutgoingContext(ctx, copied)
 }
 
 // embeds client version
@@ -42,7 +43,8 @@ func withVersion(ctx context.Context) context.Context {
 		md = metadata.Pairs(rpctypes.MetadataClientAPIVersionKey, version.APIVersion)
 		return metadata.NewOutgoingContext(ctx, md)
 	}
+	copied := md.Copy() // avoid racey updates
 	// overwrite/add version key/value
-	md.Set(rpctypes.MetadataClientAPIVersionKey, version.APIVersion)
-	return metadata.NewOutgoingContext(ctx, md)
+	copied.Set(rpctypes.MetadataClientAPIVersionKey, version.APIVersion)
+	return metadata.NewOutgoingContext(ctx, copied)
 }