diff --git a/Ladybird/AppKit/CMakeLists.txt b/Ladybird/AppKit/CMakeLists.txt
index a7ed57105ba..7bdd3f47928 100644
--- a/Ladybird/AppKit/CMakeLists.txt
+++ b/Ladybird/AppKit/CMakeLists.txt
@@ -19,6 +19,11 @@ add_executable(ladybird MACOSX_BUNDLE
     Utilities/Conversions.mm
 )
 target_include_directories(ladybird PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
+
+# FIXME: Remove this once https://openradar.appspot.com/21478051 is fixed.
+add_dependencies(ladybird patched_mac_headers)
+target_include_directories(ladybird PRIVATE "${CMAKE_BINARY_DIR}/patched_mac_headers")
+
 target_link_libraries(ladybird PRIVATE "-framework Cocoa -framework UniformTypeIdentifiers" LibUnicode)
 target_compile_options(ladybird PRIVATE
         -fobjc-arc
diff --git a/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt b/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt
index e5e3009d3c3..1eb2ae328c1 100644
--- a/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt
+++ b/Meta/Lagom/Contrib/MacPDF/CMakeLists.txt
@@ -30,6 +30,10 @@ target_link_libraries(MacPDF PRIVATE
     "-framework UniformTypeIdentifiers"
 )
 
+# FIXME: Remove this once https://openradar.appspot.com/21478051 is fixed.
+add_dependencies(MacPDF patched_mac_headers)
+target_include_directories(MacPDF PRIVATE "${CMAKE_BINARY_DIR}/patched_mac_headers")
+
 set_target_properties(MacPDF PROPERTIES
     MACOSX_BUNDLE TRUE
 
diff --git a/Meta/Lagom/Tools/CMakeLists.txt b/Meta/Lagom/Tools/CMakeLists.txt
index c5d58d9a699..2cdd2dfd249 100644
--- a/Meta/Lagom/Tools/CMakeLists.txt
+++ b/Meta/Lagom/Tools/CMakeLists.txt
@@ -17,3 +17,16 @@ add_subdirectory(PrekernelPEImageGenerator)
 add_subdirectory(IPCMagicLinter)
 
 include(jakt)
+
+if (APPLE)
+    # FIXME: Remove this once https://openradar.appspot.com/21478051 is fixed.
+    find_package(Python3 REQUIRED COMPONENTS Interpreter)
+    add_custom_command(
+        OUTPUT "${CMAKE_BINARY_DIR}/patched_mac_headers/stamp"
+        COMMAND "${Python3_EXECUTABLE}" "${SerenityOS_SOURCE_DIR}/Meta/Lagom/Tools/patch_mac_sdk_headers_for_cxx26.py" -o "${CMAKE_BINARY_DIR}/patched_mac_headers" --sdk-path "${CMAKE_OSX_SYSROOT}"
+        COMMAND "${CMAKE_COMMAND}" -E touch "${CMAKE_BINARY_DIR}/patched_mac_headers/stamp"
+        VERBATIM
+        DEPENDS "${SerenityOS_SOURCE_DIR}/Meta/Lagom/Tools/patch_mac_sdk_headers_for_cxx26.py"
+    )
+    add_custom_target(patched_mac_headers DEPENDS "${CMAKE_BINARY_DIR}/patched_mac_headers/stamp")
+endif()
diff --git a/Meta/Lagom/Tools/patch_mac_sdk_headers_for_cxx26.py b/Meta/Lagom/Tools/patch_mac_sdk_headers_for_cxx26.py
new file mode 100755
index 00000000000..2e7010384ef
--- /dev/null
+++ b/Meta/Lagom/Tools/patch_mac_sdk_headers_for_cxx26.py
@@ -0,0 +1,54 @@
+#!/usr/bin/env python3
+
+# In Xcode 26.2, Cocoa.h doesn't compile with -std=c++26,
+# https://openradar.appspot.com/21478051
+#
+# This patches up bad headers in the meantime.
+#
+# Use like this, and add `foobar` to your include search path:
+#     Meta/Lagom/patch_mac_sdk_headers_for_cxx26.py -o foobar --sdk_path $(xcrun --show-sdk-path)
+
+
+import argparse
+import os
+import subprocess
+
+
+patches = {
+    "CoreGraphics/CGImage.h": [
+        (
+         'return alpha | component | byteOrder | pixelFormat;',
+         'return (CGBitmapInfo)((CGBitmapInfo)alpha | (CGBitmapInfo)component | (CGBitmapInfo)byteOrder | (CGBitmapInfo)pixelFormat);'  # noqa: E501
+        ),
+    ],
+}
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--sdk-path', help='Path to Mac SDK', required=True)
+    parser.add_argument('-o', '--output-dir', help='Output path for the patched header files', required=True)
+    args = parser.parse_args()
+
+    sdk_path = args.sdk_path
+    if not sdk_path:
+        sdk_path = subprocess.check_output(['xcrun', '--show-sdk-path']).decode().strip()
+
+    for relative_path, replacements in patches.items():
+        framework_name, header_name = relative_path.split("/")
+        sdk_file_path = f'{sdk_path}/System/Library/Frameworks/{framework_name}.framework/Headers/{header_name}'
+        with open(sdk_file_path, "r") as f:
+            content = f.read()
+
+        for old, new in replacements:
+            content = content.replace(old, new)
+
+        output_path = f'{args.output_dir}/{relative_path}'
+        os.makedirs(os.path.dirname(output_path), exist_ok=True)
+
+        with open(output_path, "w") as f:
+            f.write(content)
+
+
+if __name__ == '__main__':
+    main()