diff --git a/entity_linkage/normalization/sgtb/requirements.txt b/entity_linkage/normalization/sgtb/requirements.txt
index d5d7703d..9add5f36 100644
--- a/entity_linkage/normalization/sgtb/requirements.txt
+++ b/entity_linkage/normalization/sgtb/requirements.txt
@@ -122,7 +122,7 @@ Pillow==4.2.1
 pkginfo==1.4.1
 ply==3.10
 prompt-toolkit==1.0.15
-protobuf==3.4.1
+protobuf==3.18.3
 psutil==5.4.0
 ptyprocess==0.5.2
 py==1.4.34