diff --git a/stix_shifter/requirements.txt b/stix_shifter/requirements.txt
index acbe2d508..0f5310361 100644
--- a/stix_shifter/requirements.txt
+++ b/stix_shifter/requirements.txt
@@ -1,5 +1,5 @@
 adal==1.2.2
-antlr4-python3-runtime==4.8
+antlr4-python3-runtime==4.9.3
 boto3==1.20.30
 flask==2.0.2
 pyOpenSSL==20.0.1