diff --git a/.changesets/fix-ffi-arguments-for-free-functions.md b/.changesets/fix-ffi-arguments-for-free-functions.md
new file mode 100644
index 000000000..986ad18d6
--- /dev/null
+++ b/.changesets/fix-ffi-arguments-for-free-functions.md
@@ -0,0 +1,6 @@
+---
+bump: "patch"
+type: "fix"
+---
+
+Fix FFI function calls missing arguments for `appsignal_free_transaction` and `appsignal_free_data` extension functions. This fixes a high CPU issue when these function calls would be retried indefinitely.
diff --git a/lib/appsignal/extension/jruby.rb b/lib/appsignal/extension/jruby.rb
index e7ef37165..5f9f8141b 100644
--- a/lib/appsignal/extension/jruby.rb
+++ b/lib/appsignal/extension/jruby.rb
@@ -83,7 +83,7 @@ def self.lib_extension
 
         # Transaction methods
         attach_function :appsignal_free_transaction,
-          [],
+          [:pointer],
           :void
         attach_function :appsignal_start_transaction,
           [:appsignal_string, :appsignal_string, :long],
@@ -191,7 +191,7 @@ def self.lib_extension
           :void
 
         # Data struct methods
-        attach_function :appsignal_free_data, [], :void
+        attach_function :appsignal_free_data, [:pointer], :void
         attach_function :appsignal_data_map_new, [], :pointer
         attach_function :appsignal_data_array_new, [], :pointer
         attach_function :appsignal_data_map_set_string,