diff --git a/main/output.c b/main/output.c
index c6ac741cab1fc..ef6be672d1c16 100644
--- a/main/output.c
+++ b/main/output.c
@@ -925,6 +925,10 @@ static inline php_output_handler_status_t php_output_handler_op(php_output_handl
 	);
 #endif
 
+	if (handler->flags & PHP_OUTPUT_HANDLER_DISABLED) {
+		return PHP_OUTPUT_HANDLER_FAILURE;
+	}
+
 	if (php_output_lock_error(context->op)) {
 		/* fatal error */
 		return PHP_OUTPUT_HANDLER_FAILURE;
diff --git a/tests/output/gh15181.phpt b/tests/output/gh15181.phpt
new file mode 100644
index 0000000000000..5fa5c272b3992
--- /dev/null
+++ b/tests/output/gh15181.phpt
@@ -0,0 +1,15 @@
+--TEST--
+Fix GH-15181 (Disabled output handler is flushed again)
+--FILE--
+<?php
+ob_start(function () {
+    throw new Exception('ob_start');
+});
+try {
+    ob_flush();
+} catch (Throwable) {}
+ob_flush();
+?>
+===DONE===
+--EXPECT--
+===DONE===