diff --git a/packages/react-native/React-Core-prebuilt.podspec b/packages/react-native/React-Core-prebuilt.podspec
index 81ffdbd933d9..23aa9df84d2d 100644
--- a/packages/react-native/React-Core-prebuilt.podspec
+++ b/packages/react-native/React-Core-prebuilt.podspec
@@ -84,11 +84,7 @@ Pod::Spec.new do |s|
       :execution_position => :before_compile,
       :script => <<-EOS
       . "$REACT_NATIVE_PATH/scripts/xcode/with-environment.sh"
-
-      CONFIG="Release"
-      if echo $GCC_PREPROCESSOR_DEFINITIONS | grep -q "DEBUG=1"; then
-        CONFIG="Debug"
-      fi
+      . "$REACT_NATIVE_PATH/scripts/xcode/resolve-prebuilt-configuration.sh"
 
       "$NODE_BINARY" "$REACT_NATIVE_PATH/scripts/replace-rncore-version.js" -c "$CONFIG" -r "#{version}" -p "$PODS_ROOT"
       EOS
diff --git a/packages/react-native/package.json b/packages/react-native/package.json
index 973f18a8b239..00520250ee25 100644
--- a/packages/react-native/package.json
+++ b/packages/react-native/package.json
@@ -119,6 +119,7 @@
     "scripts/xcode/ccache-clang.sh",
     "scripts/xcode/ccache-clang++.sh",
     "scripts/xcode/ccache.conf",
+    "scripts/xcode/resolve-prebuilt-configuration.sh",
     "scripts/xcode/with-environment.sh",
     "sdks/.hermesv1version",
     "sdks/hermes-engine",
diff --git a/packages/react-native/scripts/__tests__/resolve-prebuilt-configuration-test.js b/packages/react-native/scripts/__tests__/resolve-prebuilt-configuration-test.js
new file mode 100644
index 000000000000..6dffe7131864
--- /dev/null
+++ b/packages/react-native/scripts/__tests__/resolve-prebuilt-configuration-test.js
@@ -0,0 +1,83 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ * @noflow
+ */
+
+'use strict';
+
+const {execFileSync} = require('node:child_process');
+const path = require('node:path');
+
+const SCRIPT = path.join(
+  __dirname,
+  '..',
+  'xcode',
+  'resolve-prebuilt-configuration.sh',
+);
+
+function resolve(env) {
+  return execFileSync('/bin/sh', [SCRIPT], {
+    env: {...process.env, ...env},
+    encoding: 'utf8',
+  }).trim();
+}
+
+describe('resolve-prebuilt-configuration', () => {
+  test('defaults to Release when no debug signals are present', () => {
+    expect(
+      resolve({
+        CONFIGURATION: 'Release',
+        POD_CONFIGURATION_DEBUG: '',
+        GCC_PREPROCESSOR_DEFINITIONS: 'COCOAPODS=1',
+      }),
+    ).toBe('Release');
+  });
+
+  test('selects Debug when CONFIGURATION is Debug', () => {
+    expect(
+      resolve({
+        CONFIGURATION: 'Debug',
+        POD_CONFIGURATION_DEBUG: '',
+        GCC_PREPROCESSOR_DEFINITIONS: 'COCOAPODS=1',
+      }),
+    ).toBe('Debug');
+  });
+
+  test('selects Debug when POD_CONFIGURATION_DEBUG is YES', () => {
+    expect(
+      resolve({
+        CONFIGURATION: 'Staging',
+        POD_CONFIGURATION_DEBUG: 'YES',
+        GCC_PREPROCESSOR_DEFINITIONS: 'COCOAPODS=1',
+      }),
+    ).toBe('Debug');
+  });
+
+  test('selects Debug when DEBUG=1 is in GCC_PREPROCESSOR_DEFINITIONS', () => {
+    expect(
+      resolve({
+        CONFIGURATION: 'Custom',
+        POD_CONFIGURATION_DEBUG: '',
+        GCC_PREPROCESSOR_DEFINITIONS: 'COCOAPODS=1 DEBUG=1',
+      }),
+    ).toBe('Debug');
+  });
+
+  test('keeps Release when hermes-engine Debug lacks DEBUG=1 (static CocoaPods shape)', () => {
+    // Shared helper must not treat missing DEBUG=1 as Debug by itself —
+    // CONFIGURATION / POD_CONFIGURATION_DEBUG carry that signal.
+    // hermes-engine.podspec may OR HERMES_ENABLE_DEBUGGER=1 after sourcing.
+    expect(
+      resolve({
+        CONFIGURATION: 'Release',
+        POD_CONFIGURATION_DEBUG: '',
+        GCC_PREPROCESSOR_DEFINITIONS: 'COCOAPODS=1 HERMES_ENABLE_DEBUGGER=1',
+      }),
+    ).toBe('Release');
+  });
+});
diff --git a/packages/react-native/scripts/xcode/resolve-prebuilt-configuration.sh b/packages/react-native/scripts/xcode/resolve-prebuilt-configuration.sh
new file mode 100755
index 000000000000..01ad3cb25699
--- /dev/null
+++ b/packages/react-native/scripts/xcode/resolve-prebuilt-configuration.sh
@@ -0,0 +1,37 @@
+#!/bin/sh
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+# Resolve Debug vs Release for prebuilt iOS tarball swap script phases
+# (hermes-engine, React-Core-prebuilt, ReactNativeDependencies).
+#
+# Prefer Xcode / CocoaPods configuration signals over grepping
+# GCC_PREPROCESSOR_DEFINITIONS for DEBUG=1 alone. That def is often missing
+# on hermes-engine under static CocoaPods, which incorrectly kept Release
+# hermesvm while React-hermes compiled with HERMES_ENABLE_DEBUGGER=1
+# (undefined facebook::hermes::cdp::CDPDebugAPI::* at link).
+# See https://github.com/facebook/react-native/issues/59116
+#
+# Usage (source from a podspec script phase after with-environment.sh):
+#   . "$REACT_NATIVE_PATH/scripts/xcode/resolve-prebuilt-configuration.sh"
+#   # sets CONFIG to "Debug" or "Release"
+#
+# Usage (CLI / unit tests):
+#   ./resolve-prebuilt-configuration.sh   # prints Debug|Release
+
+CONFIG="Release"
+if [ "${CONFIGURATION:-}" = "Debug" ] || \
+   [ "${POD_CONFIGURATION_DEBUG:-}" = "YES" ] || \
+   echo "${GCC_PREPROCESSOR_DEFINITIONS:-}" | grep -q "DEBUG=1"; then
+  CONFIG="Debug"
+fi
+
+# When executed directly (not sourced), print CONFIG for tests/CLI.
+# When sourced, $0 is typically the parent shell, so we only export CONFIG.
+case "${0##*/}" in
+  resolve-prebuilt-configuration.sh)
+    printf '%s\n' "$CONFIG"
+    ;;
+esac
diff --git a/packages/react-native/sdks/hermes-engine/hermes-engine.podspec b/packages/react-native/sdks/hermes-engine/hermes-engine.podspec
index b6775c1dbfaa..821d1b99f2aa 100644
--- a/packages/react-native/sdks/hermes-engine/hermes-engine.podspec
+++ b/packages/react-native/sdks/hermes-engine/hermes-engine.podspec
@@ -94,9 +94,11 @@ Pod::Spec.new do |spec|
         :execution_position => :before_compile,
         :script => <<-EOS
         . "$REACT_NATIVE_PATH/scripts/xcode/with-environment.sh"
-
-        CONFIG="Release"
-        if echo $GCC_PREPROCESSOR_DEFINITIONS | grep -q "DEBUG=1"; then
+        . "$REACT_NATIVE_PATH/scripts/xcode/resolve-prebuilt-configuration.sh"
+        # Hermes-only: React-hermes may enable CDP via HERMES_ENABLE_DEBUGGER
+        # without DEBUG=1 on this target (static CocoaPods). Keep that signal
+        # out of the shared helper — it is not meaningful for RNCore / RNDeps.
+        if [ "$CONFIG" != "Debug" ] && echo "${GCC_PREPROCESSOR_DEFINITIONS:-}" | grep -q "HERMES_ENABLE_DEBUGGER=1"; then
           CONFIG="Debug"
         fi
 
diff --git a/packages/react-native/third-party-podspecs/ReactNativeDependencies.podspec b/packages/react-native/third-party-podspecs/ReactNativeDependencies.podspec
index a006f2c1e4ca..a86fad539fd8 100644
--- a/packages/react-native/third-party-podspecs/ReactNativeDependencies.podspec
+++ b/packages/react-native/third-party-podspecs/ReactNativeDependencies.podspec
@@ -76,11 +76,7 @@ Pod::Spec.new do |spec|
       :execution_position => :before_compile,
       :script => <<-EOS
       . "$REACT_NATIVE_PATH/scripts/xcode/with-environment.sh"
-
-      CONFIG="Release"
-      if echo $GCC_PREPROCESSOR_DEFINITIONS | grep -q "DEBUG=1"; then
-        CONFIG="Debug"
-      fi
+      . "$REACT_NATIVE_PATH/scripts/xcode/resolve-prebuilt-configuration.sh"
 
       "$NODE_BINARY" "$REACT_NATIVE_PATH/third-party-podspecs/replace_dependencies_version.js" -c "$CONFIG" -r "#{version}" -p "$PODS_ROOT"
       EOS