diff --git a/compiled/facebook-www/REVISION b/compiled/facebook-www/REVISION
index 4eb3ea66224f9..272b4a9a4fd96 100644
--- a/compiled/facebook-www/REVISION
+++ b/compiled/facebook-www/REVISION
@@ -1 +1 @@
-5d29478716cefbf8290dfdd19129156c2ac75973
+6bac4f2f31378cd58dffe6181e00639366a6081a
diff --git a/compiled/facebook-www/ReactDOMServer-dev.classic.js b/compiled/facebook-www/ReactDOMServer-dev.classic.js
index f4e58b2ca311a..2775b030c1368 100644
--- a/compiled/facebook-www/ReactDOMServer-dev.classic.js
+++ b/compiled/facebook-www/ReactDOMServer-dev.classic.js
@@ -19,7 +19,7 @@ if (__DEV__) {
 var React = require('react');
 var ReactDOM = require('react-dom');
 
-var ReactVersion = '19.0.0-www-classic-f3d84129';
+var ReactVersion = '19.0.0-www-classic-b547cfd9';
 
 // This refers to a WWW module.
 var warningWWW = require('warning');
@@ -2572,11 +2572,7 @@ var startHiddenInputChunk = stringToPrecomputedChunk('<input type="hidden"');
 function pushAdditionalFormField(value, key) {
   var target = this;
   target.push(startHiddenInputChunk);
-
-  if (typeof value !== 'string') {
-    throw new Error('File/Blob fields are not yet supported in progressive forms. ' + 'It probably means you are closing over binary data or FormData in a Server Action.');
-  }
-
+  validateAdditionalFormField(value);
   pushStringAttribute(target, 'name', key);
   pushStringAttribute(target, 'value', value);
   target.push(endOfStartTagSelfClosing);
@@ -2589,6 +2585,21 @@ function pushAdditionalFormFields(target, formData) {
   }
 }
 
+function validateAdditionalFormField(value, key) {
+  if (typeof value !== 'string') {
+    throw new Error('File/Blob fields are not yet supported in progressive forms. ' + 'Will fallback to client hydration.');
+  }
+}
+
+function validateAdditionalFormFields(formData) {
+  if (formData != null) {
+    // $FlowFixMe[prop-missing]: FormData has forEach.
+    formData.forEach(validateAdditionalFormField);
+  }
+
+  return formData;
+}
+
 function getCustomFormFields(resumableState, formAction) {
   var customAction = formAction.$$FORM_ACTION;
 
@@ -2596,7 +2607,13 @@ function getCustomFormFields(resumableState, formAction) {
     var prefix = makeFormFieldPrefix(resumableState);
 
     try {
-      return formAction.$$FORM_ACTION(prefix);
+      var customFields = formAction.$$FORM_ACTION(prefix);
+
+      if (customFields) {
+        validateAdditionalFormFields(customFields.data);
+      }
+
+      return customFields;
     } catch (x) {
       if (typeof x === 'object' && x !== null && typeof x.then === 'function') {
         // Rethrow suspense.
diff --git a/compiled/facebook-www/ReactDOMServer-dev.modern.js b/compiled/facebook-www/ReactDOMServer-dev.modern.js
index 1488583b352a2..b3b1077ebf4bf 100644
--- a/compiled/facebook-www/ReactDOMServer-dev.modern.js
+++ b/compiled/facebook-www/ReactDOMServer-dev.modern.js
@@ -19,7 +19,7 @@ if (__DEV__) {
 var React = require('react');
 var ReactDOM = require('react-dom');
 
-var ReactVersion = '19.0.0-www-modern-f9bdfca0';
+var ReactVersion = '19.0.0-www-modern-ce28692a';
 
 // This refers to a WWW module.
 var warningWWW = require('warning');
@@ -2572,11 +2572,7 @@ var startHiddenInputChunk = stringToPrecomputedChunk('<input type="hidden"');
 function pushAdditionalFormField(value, key) {
   var target = this;
   target.push(startHiddenInputChunk);
-
-  if (typeof value !== 'string') {
-    throw new Error('File/Blob fields are not yet supported in progressive forms. ' + 'It probably means you are closing over binary data or FormData in a Server Action.');
-  }
-
+  validateAdditionalFormField(value);
   pushStringAttribute(target, 'name', key);
   pushStringAttribute(target, 'value', value);
   target.push(endOfStartTagSelfClosing);
@@ -2589,6 +2585,21 @@ function pushAdditionalFormFields(target, formData) {
   }
 }
 
+function validateAdditionalFormField(value, key) {
+  if (typeof value !== 'string') {
+    throw new Error('File/Blob fields are not yet supported in progressive forms. ' + 'Will fallback to client hydration.');
+  }
+}
+
+function validateAdditionalFormFields(formData) {
+  if (formData != null) {
+    // $FlowFixMe[prop-missing]: FormData has forEach.
+    formData.forEach(validateAdditionalFormField);
+  }
+
+  return formData;
+}
+
 function getCustomFormFields(resumableState, formAction) {
   var customAction = formAction.$$FORM_ACTION;
 
@@ -2596,7 +2607,13 @@ function getCustomFormFields(resumableState, formAction) {
     var prefix = makeFormFieldPrefix(resumableState);
 
     try {
-      return formAction.$$FORM_ACTION(prefix);
+      var customFields = formAction.$$FORM_ACTION(prefix);
+
+      if (customFields) {
+        validateAdditionalFormFields(customFields.data);
+      }
+
+      return customFields;
     } catch (x) {
       if (typeof x === 'object' && x !== null && typeof x.then === 'function') {
         // Rethrow suspense.
diff --git a/compiled/facebook-www/ReactDOMServer-prod.classic.js b/compiled/facebook-www/ReactDOMServer-prod.classic.js
index 6bb3aed38155d..c921771d5a510 100644
--- a/compiled/facebook-www/ReactDOMServer-prod.classic.js
+++ b/compiled/facebook-www/ReactDOMServer-prod.classic.js
@@ -445,17 +445,25 @@ var actionJavaScriptURL = escapeTextForBrowser(
 );
 function pushAdditionalFormField(value, key) {
   this.push('<input type="hidden"');
-  if ("string" !== typeof value) throw Error(formatProdErrorMessage(480));
+  validateAdditionalFormField(value);
   pushStringAttribute(this, "name", key);
   pushStringAttribute(this, "value", value);
   this.push("/>");
 }
+function validateAdditionalFormField(value) {
+  if ("string" !== typeof value) throw Error(formatProdErrorMessage(480));
+}
 function getCustomFormFields(resumableState, formAction) {
   if ("function" === typeof formAction.$$FORM_ACTION) {
     var id = resumableState.nextFormID++;
     resumableState = resumableState.idPrefix + id;
     try {
-      return formAction.$$FORM_ACTION(resumableState);
+      var customFields = formAction.$$FORM_ACTION(resumableState);
+      if (customFields) {
+        var formData = customFields.data;
+        null != formData && formData.forEach(validateAdditionalFormField);
+      }
+      return customFields;
     } catch (x) {
       if ("object" === typeof x && null !== x && "function" === typeof x.then)
         throw x;
@@ -2627,16 +2635,16 @@ function createRenderState(resumableState, generateStaticMarkup) {
       "\x3c/script>"
     );
   bootstrapScriptContent = idPrefix + "P:";
-  var JSCompiler_object_inline_segmentPrefix_1631 = idPrefix + "S:";
+  var JSCompiler_object_inline_segmentPrefix_1633 = idPrefix + "S:";
   idPrefix += "B:";
-  var JSCompiler_object_inline_preconnects_1645 = new Set(),
-    JSCompiler_object_inline_fontPreloads_1646 = new Set(),
-    JSCompiler_object_inline_highImagePreloads_1647 = new Set(),
-    JSCompiler_object_inline_styles_1648 = new Map(),
-    JSCompiler_object_inline_bootstrapScripts_1649 = new Set(),
-    JSCompiler_object_inline_scripts_1650 = new Set(),
-    JSCompiler_object_inline_bulkPreloads_1651 = new Set(),
-    JSCompiler_object_inline_preloads_1652 = {
+  var JSCompiler_object_inline_preconnects_1647 = new Set(),
+    JSCompiler_object_inline_fontPreloads_1648 = new Set(),
+    JSCompiler_object_inline_highImagePreloads_1649 = new Set(),
+    JSCompiler_object_inline_styles_1650 = new Map(),
+    JSCompiler_object_inline_bootstrapScripts_1651 = new Set(),
+    JSCompiler_object_inline_scripts_1652 = new Set(),
+    JSCompiler_object_inline_bulkPreloads_1653 = new Set(),
+    JSCompiler_object_inline_preloads_1654 = {
       images: new Map(),
       stylesheets: new Map(),
       scripts: new Map(),
@@ -2673,7 +2681,7 @@ function createRenderState(resumableState, generateStaticMarkup) {
       scriptConfig.moduleScriptResources[href] = null;
       scriptConfig = [];
       pushLinkImpl(scriptConfig, props);
-      JSCompiler_object_inline_bootstrapScripts_1649.add(scriptConfig);
+      JSCompiler_object_inline_bootstrapScripts_1651.add(scriptConfig);
       bootstrapChunks.push('<script src="', escapeTextForBrowser(src));
       "string" === typeof integrity &&
         bootstrapChunks.push('" integrity="', escapeTextForBrowser(integrity));
@@ -2714,7 +2722,7 @@ function createRenderState(resumableState, generateStaticMarkup) {
         (props.moduleScriptResources[scriptConfig] = null),
         (props = []),
         pushLinkImpl(props, integrity),
-        JSCompiler_object_inline_bootstrapScripts_1649.add(props),
+        JSCompiler_object_inline_bootstrapScripts_1651.add(props),
         bootstrapChunks.push(
           '<script type="module" src="',
           escapeTextForBrowser(i)
@@ -2729,7 +2737,7 @@ function createRenderState(resumableState, generateStaticMarkup) {
         bootstrapChunks.push('" async="">\x3c/script>');
   return {
     placeholderPrefix: bootstrapScriptContent,
-    segmentPrefix: JSCompiler_object_inline_segmentPrefix_1631,
+    segmentPrefix: JSCompiler_object_inline_segmentPrefix_1633,
     boundaryPrefix: idPrefix,
     startInlineScript: "<script>",
     htmlChunks: null,
@@ -2749,14 +2757,14 @@ function createRenderState(resumableState, generateStaticMarkup) {
     charsetChunks: [],
     viewportChunks: [],
     hoistableChunks: [],
-    preconnects: JSCompiler_object_inline_preconnects_1645,
-    fontPreloads: JSCompiler_object_inline_fontPreloads_1646,
-    highImagePreloads: JSCompiler_object_inline_highImagePreloads_1647,
-    styles: JSCompiler_object_inline_styles_1648,
-    bootstrapScripts: JSCompiler_object_inline_bootstrapScripts_1649,
-    scripts: JSCompiler_object_inline_scripts_1650,
-    bulkPreloads: JSCompiler_object_inline_bulkPreloads_1651,
-    preloads: JSCompiler_object_inline_preloads_1652,
+    preconnects: JSCompiler_object_inline_preconnects_1647,
+    fontPreloads: JSCompiler_object_inline_fontPreloads_1648,
+    highImagePreloads: JSCompiler_object_inline_highImagePreloads_1649,
+    styles: JSCompiler_object_inline_styles_1650,
+    bootstrapScripts: JSCompiler_object_inline_bootstrapScripts_1651,
+    scripts: JSCompiler_object_inline_scripts_1652,
+    bulkPreloads: JSCompiler_object_inline_bulkPreloads_1653,
+    preloads: JSCompiler_object_inline_preloads_1654,
     stylesToHoist: !1,
     generateStaticMarkup: generateStaticMarkup
   };
@@ -5691,4 +5699,4 @@ exports.renderToString = function (children, options) {
     'The server used "renderToString" which does not support Suspense. If you intended for this Suspense boundary to render the fallback content on the server consider throwing an Error somewhere within the Suspense boundary. If you intended to have the server wait for the suspended component please switch to "renderToReadableStream" which supports Suspense on the server'
   );
 };
-exports.version = "19.0.0-www-classic-a976e819";
+exports.version = "19.0.0-www-classic-444074d7";
diff --git a/compiled/facebook-www/ReactDOMServer-prod.modern.js b/compiled/facebook-www/ReactDOMServer-prod.modern.js
index 255e6c1ec8376..c0707f8cd7291 100644
--- a/compiled/facebook-www/ReactDOMServer-prod.modern.js
+++ b/compiled/facebook-www/ReactDOMServer-prod.modern.js
@@ -445,17 +445,25 @@ var actionJavaScriptURL = escapeTextForBrowser(
 );
 function pushAdditionalFormField(value, key) {
   this.push('<input type="hidden"');
-  if ("string" !== typeof value) throw Error(formatProdErrorMessage(480));
+  validateAdditionalFormField(value);
   pushStringAttribute(this, "name", key);
   pushStringAttribute(this, "value", value);
   this.push("/>");
 }
+function validateAdditionalFormField(value) {
+  if ("string" !== typeof value) throw Error(formatProdErrorMessage(480));
+}
 function getCustomFormFields(resumableState, formAction) {
   if ("function" === typeof formAction.$$FORM_ACTION) {
     var id = resumableState.nextFormID++;
     resumableState = resumableState.idPrefix + id;
     try {
-      return formAction.$$FORM_ACTION(resumableState);
+      var customFields = formAction.$$FORM_ACTION(resumableState);
+      if (customFields) {
+        var formData = customFields.data;
+        null != formData && formData.forEach(validateAdditionalFormField);
+      }
+      return customFields;
     } catch (x) {
       if ("object" === typeof x && null !== x && "function" === typeof x.then)
         throw x;
@@ -2627,16 +2635,16 @@ function createRenderState(resumableState, generateStaticMarkup) {
       "\x3c/script>"
     );
   bootstrapScriptContent = idPrefix + "P:";
-  var JSCompiler_object_inline_segmentPrefix_1618 = idPrefix + "S:";
+  var JSCompiler_object_inline_segmentPrefix_1620 = idPrefix + "S:";
   idPrefix += "B:";
-  var JSCompiler_object_inline_preconnects_1632 = new Set(),
-    JSCompiler_object_inline_fontPreloads_1633 = new Set(),
-    JSCompiler_object_inline_highImagePreloads_1634 = new Set(),
-    JSCompiler_object_inline_styles_1635 = new Map(),
-    JSCompiler_object_inline_bootstrapScripts_1636 = new Set(),
-    JSCompiler_object_inline_scripts_1637 = new Set(),
-    JSCompiler_object_inline_bulkPreloads_1638 = new Set(),
-    JSCompiler_object_inline_preloads_1639 = {
+  var JSCompiler_object_inline_preconnects_1634 = new Set(),
+    JSCompiler_object_inline_fontPreloads_1635 = new Set(),
+    JSCompiler_object_inline_highImagePreloads_1636 = new Set(),
+    JSCompiler_object_inline_styles_1637 = new Map(),
+    JSCompiler_object_inline_bootstrapScripts_1638 = new Set(),
+    JSCompiler_object_inline_scripts_1639 = new Set(),
+    JSCompiler_object_inline_bulkPreloads_1640 = new Set(),
+    JSCompiler_object_inline_preloads_1641 = {
       images: new Map(),
       stylesheets: new Map(),
       scripts: new Map(),
@@ -2673,7 +2681,7 @@ function createRenderState(resumableState, generateStaticMarkup) {
       scriptConfig.moduleScriptResources[href] = null;
       scriptConfig = [];
       pushLinkImpl(scriptConfig, props);
-      JSCompiler_object_inline_bootstrapScripts_1636.add(scriptConfig);
+      JSCompiler_object_inline_bootstrapScripts_1638.add(scriptConfig);
       bootstrapChunks.push('<script src="', escapeTextForBrowser(src));
       "string" === typeof integrity &&
         bootstrapChunks.push('" integrity="', escapeTextForBrowser(integrity));
@@ -2714,7 +2722,7 @@ function createRenderState(resumableState, generateStaticMarkup) {
         (props.moduleScriptResources[scriptConfig] = null),
         (props = []),
         pushLinkImpl(props, integrity),
-        JSCompiler_object_inline_bootstrapScripts_1636.add(props),
+        JSCompiler_object_inline_bootstrapScripts_1638.add(props),
         bootstrapChunks.push(
           '<script type="module" src="',
           escapeTextForBrowser(i)
@@ -2729,7 +2737,7 @@ function createRenderState(resumableState, generateStaticMarkup) {
         bootstrapChunks.push('" async="">\x3c/script>');
   return {
     placeholderPrefix: bootstrapScriptContent,
-    segmentPrefix: JSCompiler_object_inline_segmentPrefix_1618,
+    segmentPrefix: JSCompiler_object_inline_segmentPrefix_1620,
     boundaryPrefix: idPrefix,
     startInlineScript: "<script>",
     htmlChunks: null,
@@ -2749,14 +2757,14 @@ function createRenderState(resumableState, generateStaticMarkup) {
     charsetChunks: [],
     viewportChunks: [],
     hoistableChunks: [],
-    preconnects: JSCompiler_object_inline_preconnects_1632,
-    fontPreloads: JSCompiler_object_inline_fontPreloads_1633,
-    highImagePreloads: JSCompiler_object_inline_highImagePreloads_1634,
-    styles: JSCompiler_object_inline_styles_1635,
-    bootstrapScripts: JSCompiler_object_inline_bootstrapScripts_1636,
-    scripts: JSCompiler_object_inline_scripts_1637,
-    bulkPreloads: JSCompiler_object_inline_bulkPreloads_1638,
-    preloads: JSCompiler_object_inline_preloads_1639,
+    preconnects: JSCompiler_object_inline_preconnects_1634,
+    fontPreloads: JSCompiler_object_inline_fontPreloads_1635,
+    highImagePreloads: JSCompiler_object_inline_highImagePreloads_1636,
+    styles: JSCompiler_object_inline_styles_1637,
+    bootstrapScripts: JSCompiler_object_inline_bootstrapScripts_1638,
+    scripts: JSCompiler_object_inline_scripts_1639,
+    bulkPreloads: JSCompiler_object_inline_bulkPreloads_1640,
+    preloads: JSCompiler_object_inline_preloads_1641,
     stylesToHoist: !1,
     generateStaticMarkup: generateStaticMarkup
   };
@@ -5669,4 +5677,4 @@ exports.renderToString = function (children, options) {
     'The server used "renderToString" which does not support Suspense. If you intended for this Suspense boundary to render the fallback content on the server consider throwing an Error somewhere within the Suspense boundary. If you intended to have the server wait for the suspended component please switch to "renderToReadableStream" which supports Suspense on the server'
   );
 };
-exports.version = "19.0.0-www-modern-54e820e3";
+exports.version = "19.0.0-www-modern-df91acfc";
diff --git a/compiled/facebook-www/ReactDOMServerStreaming-dev.modern.js b/compiled/facebook-www/ReactDOMServerStreaming-dev.modern.js
index d3625a388c3db..2b44cdb8ae5d1 100644
--- a/compiled/facebook-www/ReactDOMServerStreaming-dev.modern.js
+++ b/compiled/facebook-www/ReactDOMServerStreaming-dev.modern.js
@@ -2569,11 +2569,7 @@ var startHiddenInputChunk = stringToPrecomputedChunk('<input type="hidden"');
 function pushAdditionalFormField(value, key) {
   var target = this;
   target.push(startHiddenInputChunk);
-
-  if (typeof value !== 'string') {
-    throw new Error('File/Blob fields are not yet supported in progressive forms. ' + 'It probably means you are closing over binary data or FormData in a Server Action.');
-  }
-
+  validateAdditionalFormField(value);
   pushStringAttribute(target, 'name', key);
   pushStringAttribute(target, 'value', value);
   target.push(endOfStartTagSelfClosing);
@@ -2586,6 +2582,21 @@ function pushAdditionalFormFields(target, formData) {
   }
 }
 
+function validateAdditionalFormField(value, key) {
+  if (typeof value !== 'string') {
+    throw new Error('File/Blob fields are not yet supported in progressive forms. ' + 'Will fallback to client hydration.');
+  }
+}
+
+function validateAdditionalFormFields(formData) {
+  if (formData != null) {
+    // $FlowFixMe[prop-missing]: FormData has forEach.
+    formData.forEach(validateAdditionalFormField);
+  }
+
+  return formData;
+}
+
 function getCustomFormFields(resumableState, formAction) {
   var customAction = formAction.$$FORM_ACTION;
 
@@ -2593,7 +2604,13 @@ function getCustomFormFields(resumableState, formAction) {
     var prefix = makeFormFieldPrefix(resumableState);
 
     try {
-      return formAction.$$FORM_ACTION(prefix);
+      var customFields = formAction.$$FORM_ACTION(prefix);
+
+      if (customFields) {
+        validateAdditionalFormFields(customFields.data);
+      }
+
+      return customFields;
     } catch (x) {
       if (typeof x === 'object' && x !== null && typeof x.then === 'function') {
         // Rethrow suspense.
diff --git a/compiled/facebook-www/ReactDOMServerStreaming-prod.modern.js b/compiled/facebook-www/ReactDOMServerStreaming-prod.modern.js
index 45f03e90bddf8..1eb87eb8c4c87 100644
--- a/compiled/facebook-www/ReactDOMServerStreaming-prod.modern.js
+++ b/compiled/facebook-www/ReactDOMServerStreaming-prod.modern.js
@@ -417,20 +417,28 @@ var actionJavaScriptURL = escapeTextForBrowser(
 );
 function pushAdditionalFormField(value, key) {
   this.push('<input type="hidden"');
-  if ("string" !== typeof value)
-    throw Error(
-      "File/Blob fields are not yet supported in progressive forms. It probably means you are closing over binary data or FormData in a Server Action."
-    );
+  validateAdditionalFormField(value);
   pushStringAttribute(this, "name", key);
   pushStringAttribute(this, "value", value);
   this.push("/>");
 }
+function validateAdditionalFormField(value) {
+  if ("string" !== typeof value)
+    throw Error(
+      "File/Blob fields are not yet supported in progressive forms. Will fallback to client hydration."
+    );
+}
 function getCustomFormFields(resumableState, formAction) {
   if ("function" === typeof formAction.$$FORM_ACTION) {
     var id = resumableState.nextFormID++;
     resumableState = resumableState.idPrefix + id;
     try {
-      return formAction.$$FORM_ACTION(resumableState);
+      var customFields = formAction.$$FORM_ACTION(resumableState);
+      if (customFields) {
+        var formData = customFields.data;
+        null != formData && formData.forEach(validateAdditionalFormField);
+      }
+      return customFields;
     } catch (x) {
       if ("object" === typeof x && null !== x && "function" === typeof x.then)
         throw x;