diff --git a/packages/builder/src/components/design/settings/componentSettings.js b/packages/builder/src/components/design/settings/componentSettings.js
index 927c2d9175..7ccc7a6463 100644
--- a/packages/builder/src/components/design/settings/componentSettings.js
+++ b/packages/builder/src/components/design/settings/componentSettings.js
@@ -86,6 +86,7 @@ const componentMap = {
   "validation/boolean": ValidationEditor,
   "validation/datetime": ValidationEditor,
   "validation/attachment": ValidationEditor,
+  "validation/attachment_single": ValidationEditor,
   "validation/signature": ValidationEditor,
   "validation/link": ValidationEditor,
   "validation/bb_reference": ValidationEditor,
diff --git a/packages/builder/src/components/design/settings/controls/ValidationEditor/ValidationDrawer.svelte b/packages/builder/src/components/design/settings/controls/ValidationEditor/ValidationDrawer.svelte
index 29ce0bd064..eb1f7988fc 100644
--- a/packages/builder/src/components/design/settings/controls/ValidationEditor/ValidationDrawer.svelte
+++ b/packages/builder/src/components/design/settings/controls/ValidationEditor/ValidationDrawer.svelte
@@ -108,6 +108,7 @@
       Constraints.MaxFileSize,
       Constraints.MaxUploadSize,
     ],
+    ["attachment_single"]: [Constraints.Required, Constraints.MaxUploadSize],
     ["signature"]: [Constraints.Required],
     ["link"]: [
       Constraints.Required,
diff --git a/packages/client/manifest.json b/packages/client/manifest.json
index 0637004e36..9084a25753 100644
--- a/packages/client/manifest.json
+++ b/packages/client/manifest.json
@@ -4427,7 +4427,7 @@
         "defaultValue": false
       },
       {
-        "type": "validation/attachment",
+        "type": "validation/attachment_single",
         "label": "Validation",
         "key": "validation"
       },
diff --git a/packages/client/src/components/app/forms/validation.js b/packages/client/src/components/app/forms/validation.js
index 903e1a47e7..5dfeb09f46 100644
--- a/packages/client/src/components/app/forms/validation.js
+++ b/packages/client/src/components/app/forms/validation.js
@@ -199,6 +199,14 @@ const parseType = (value, type) => {
     return value
   }
 
+  // Parse attachment single, treating no key as null
+  if (type === FieldTypes.ATTACHMENT_SINGLE) {
+    if (!value?.key) {
+      return null
+    }
+    return value
+  }
+
   // Parse links, treating no elements as null
   if (type === FieldTypes.LINK) {
     if (!Array.isArray(value) || !value.length) {
@@ -245,10 +253,8 @@ const maxLengthHandler = (value, rule) => {
 // Evaluates a max file size (MB) constraint
 const maxFileSizeHandler = (value, rule) => {
   const limit = parseType(rule.value, "number")
-  return (
-    value == null ||
-    !value.some(attachment => attachment.size / 1000000 > limit)
-  )
+  const check = attachment => attachment.size / 1000000 > limit
+  return value == null || !(value?.key ? check(value) : value.some(check))
 }
 
 // Evaluates a max total upload size (MB) constraint
@@ -256,8 +262,11 @@ const maxUploadSizeHandler = (value, rule) => {
   const limit = parseType(rule.value, "number")
   return (
     value == null ||
-    value.reduce((acc, currentItem) => acc + currentItem.size, 0) / 1000000 <=
-      limit
+    (value?.key
+      ? value.size / 1000000 <= limit
+      : value.reduce((acc, currentItem) => acc + currentItem.size, 0) /
+          1000000 <=
+        limit)
   )
 }