AWS AWSCloudFormation documentation change

Service: AWSCloudFormation · 2025-09-19 · Documentation medium

File: AWSCloudFormation/latest/TemplateReference/aws-properties-evs-environment-initialvlans.md

Summary

Added HCX network configuration properties and public VLAN requirements documentation

Security assessment

Added network ACL ID and public/private VLAN configuration options with security requirements (public CIDR needs, EIP allocation). While these relate to network security configuration, there's no evidence of addressing a specific security vulnerability.

Diff

diff --git a/AWSCloudFormation/latest/TemplateReference/aws-properties-evs-environment-initialvlans.md b/AWSCloudFormation/latest/TemplateReference/aws-properties-evs-environment-initialvlans.md
index 89906f3d6..503b93d87 100644
--- a//AWSCloudFormation/latest/TemplateReference/aws-properties-evs-environment-initialvlans.md
+++ b//AWSCloudFormation/latest/TemplateReference/aws-properties-evs-environment-initialvlans.md
@@ -22,0 +23,2 @@ To declare this entity in your AWS CloudFormation template, use the following sy
+      "HcxNetworkAclId" : String,
+      "IsHcxPublic" : Boolean,
@@ -42,0 +45,2 @@ To declare this entity in your AWS CloudFormation template, use the following sy
+      HcxNetworkAclId: String
+      IsHcxPublic: Boolean
@@ -96,0 +101,11 @@ The HCX VLAN subnet. This VLAN subnet allows the HCX Interconnnect (IX) and HCX
+If you plan to use a public HCX VLAN subnet, the following requirements must be met:
+
+  * Must have a /28 netmask and be allocated from the IPAM public pool. Required for HCX internet access configuration.
+
+  * The HCX public VLAN CIDR block must be added to the VPC as a secondary CIDR block.
+
+  * Must have at least two Elastic IP addresses to be allocated from the public IPAM pool for HCX components.
+
+
+
+
@@ -102,0 +118,24 @@ _Required_ : Yes
+`HcxNetworkAclId`
+    
+
+A unique ID for a network access control list that the HCX VLAN uses. Required when `isHcxPublic` is set to `true`.
+
+_Required_ : No
+
+ _Type_ : String
+
+ _Pattern_ : `^acl-[a-zA-Z0-9_-]+$`
+
+_Update requires_ : [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)
+
+`IsHcxPublic`
+    
+
+Determines if the HCX VLAN that Amazon EVS provisions is public or private.
+
+_Required_ : No
+
+ _Type_ : Boolean
+
+ _Update requires_ : [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)
+