From 1df5af32b87afa6cdf5dac1eaab61c5ebf1fced4 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 20 Jul 2026 10:45:13 +0000
Subject: [PATCH] fix(vm): block VM creation with invalid CloudInit YAML
 content

---
 ...erhci.io.virtualmachinetemplateversion.vue | 28 +++++++++++++++++++
 .../edit/kubevirt.io.virtualmachine/index.vue | 24 ++++++++++++++++
 pkg/harvester/l10n/en-us.yaml                 |  2 ++
 3 files changed, 54 insertions(+)

diff --git a/pkg/harvester/edit/harvesterhci.io.virtualmachinetemplateversion.vue b/pkg/harvester/edit/harvesterhci.io.virtualmachinetemplateversion.vue
index bdded934..769113ca 100644
--- a/pkg/harvester/edit/harvesterhci.io.virtualmachinetemplateversion.vue
+++ b/pkg/harvester/edit/harvesterhci.io.virtualmachinetemplateversion.vue
@@ -1,4 +1,5 @@
 <script>
+import jsyaml from 'js-yaml';
 import { mapGetters } from 'vuex';
 import Tabbed from '@shell/components/Tabbed';
 import Tab from '@shell/components/Tabbed/Tab';
@@ -177,8 +178,17 @@ export default {
     },
 
     async saveVMT(buttonCb) {
+      this.errors = [];
       this.parseVM();
 
+      this.validateCloudInit();
+
+      if (this.errors.length) {
+        buttonCb(false);
+
+        return;
+      }
+
       const templates = await this.$store.dispatch('harvester/findAll', { type: HCI.VM_TEMPLATE });
       const template = templates.find( (O) => O.metadata.name === this.templateValue.metadata.name);
 
@@ -237,6 +247,24 @@ export default {
         this.$refs.yamlEditor?.refresh();
       }
     },
+
+    validateCloudInit() {
+      if (this.userScript) {
+        try {
+          jsyaml.load(this.userScript);
+        } catch (e) {
+          this.errors.push(this.t('harvester.virtualMachine.cloudConfig.user.invalidYaml'));
+        }
+      }
+
+      if (this.networkScript) {
+        try {
+          jsyaml.load(this.networkScript);
+        } catch (e) {
+          this.errors.push(this.t('harvester.virtualMachine.cloudConfig.network.invalidYaml'));
+        }
+      }
+    },
   },
 };
 </script>
diff --git a/pkg/harvester/edit/kubevirt.io.virtualmachine/index.vue b/pkg/harvester/edit/kubevirt.io.virtualmachine/index.vue
index b712cc5b..c2c4b17f 100644
--- a/pkg/harvester/edit/kubevirt.io.virtualmachine/index.vue
+++ b/pkg/harvester/edit/kubevirt.io.virtualmachine/index.vue
@@ -1,4 +1,5 @@
 <script>
+import jsyaml from 'js-yaml';
 import { isEqual } from 'lodash';
 import { mapGetters } from 'vuex';
 import Tabbed from '@shell/components/Tabbed';
@@ -379,6 +380,7 @@ export default {
 
       this.validateCPUMemory();
       this.validateWindowsSysprep();
+      this.validateCloudInit();
 
       // block create VM flow if has validation errors
       if (this.errors.length) {
@@ -424,6 +426,28 @@ export default {
       }
     },
 
+    validateCloudInit() {
+      if (this.isWindows) {
+        return;
+      }
+
+      if (this.userScript) {
+        try {
+          jsyaml.load(this.userScript);
+        } catch (e) {
+          this.errors.push(this.t('harvester.virtualMachine.cloudConfig.user.invalidYaml'));
+        }
+      }
+
+      if (this.networkScript) {
+        try {
+          jsyaml.load(this.networkScript);
+        } catch (e) {
+          this.errors.push(this.t('harvester.virtualMachine.cloudConfig.network.invalidYaml'));
+        }
+      }
+    },
+
     async saveSingle(buttonCb) {
       this.parseVM();
       this.value.spec.template.spec.hostname = this.hostname ? this.hostname : this.value.metadata.name;
diff --git a/pkg/harvester/l10n/en-us.yaml b/pkg/harvester/l10n/en-us.yaml
index 3902c094..a8f393af 100644
--- a/pkg/harvester/l10n/en-us.yaml
+++ b/pkg/harvester/l10n/en-us.yaml
@@ -830,10 +830,12 @@ harvester:
         label: User Data Template
         title: "User Data:"
         tip: "You can specify user data to configure an instance or run a configuration script during launch. If you launch more than one instance at a time, the user data is available to all the instances in that reservation. <a href='https://cloudinit.readthedocs.io/en/latest/topics/examples.html' target='_blank'>Learn more</a>"
+        invalidYaml: 'Invalid User Data YAML syntax'
       network:
         label: Network Data Template
         title: "Network Data:"
         tip: "The network-data configuration allows you to customize the instance's networking interfaces by assigning subnet configuration, virtual device creation (bonds, bridges, VLANs) routes and DNS configuration. <a href='https://cloudinit.readthedocs.io/en/latest/reference/network-config-format-v1.html' target='_blank'>Learn more</a>"
+        invalidYaml: 'Invalid Network Data YAML syntax'
     sysprep:
       title: Windows Sysprep Configuration
       description: "Configure Windows automated installation using autounattend.xml. The configuration will be stored in a Kubernetes Secret and mounted as a CD-ROM during installation. <a href='https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/automate-windows-setup' target='_blank'>Learn more</a>"