diff --git a/src/lambda_codebase/initial_commit/bootstrap_repository/adf-build/shared/python/cloudformation.py b/src/lambda_codebase/initial_commit/bootstrap_repository/adf-build/shared/python/cloudformation.py
index b750167b1..0b2d389f8 100644
--- a/src/lambda_codebase/initial_commit/bootstrap_repository/adf-build/shared/python/cloudformation.py
+++ b/src/lambda_codebase/initial_commit/bootstrap_repository/adf-build/shared/python/cloudformation.py
@@ -21,7 +21,8 @@
         max_attempts=10
     )
 )
-CFN_UNACCEPTED_CHARS = re.compile(r"[^-a-zA-Z0-9:/._+]")
+# A stack name can contain only alphanumeric characters (case sensitive) and hyphens.
+CFN_UNACCEPTED_CHARS = re.compile(r"[^-a-zA-Z0-9]")
 
 class StackProperties:
     clean_stack_status = [