diff -Naur php-5.2.6.orig/main/main.c php-5.2.6.back/main/main.c
--- php-5.2.6.orig/main/main.c	2008-03-05 15:58:08.000000000 -0500
+++ php-5.2.6.back/main/main.c	2008-09-01 22:19:24.000000000 -0400
@@ -972,6 +985,7 @@
 		case E_PARSE:
 		case E_COMPILE_ERROR:
 		case E_USER_ERROR:
+			EG(stack_nbr) = 0;
 			EG(exit_status) = 255;
 			if (module_initialized) {
 				if (!PG(display_errors) &&
@@ -1930,6 +1989,7 @@
 #endif
 	int retval = 0;
 
+	EG(stack_nbr) = 0;
 	EG(exit_status) = 0;
 	if (php_handle_special_queries(TSRMLS_C)) {
 		zend_file_handle_dtor(primary_file);
@@ -2027,6 +2087,7 @@
 {
 	char *old_cwd;
 
+	EG(stack_nbr) = 0;
 	EG(exit_status) = 0;
 #define OLD_CWD_SIZE 4096
 	old_cwd = do_alloca(OLD_CWD_SIZE);
diff -Naur php-5.2.6.orig/Zend/zend.c php-5.2.6.back/Zend/zend.c
--- php-5.2.6.orig/Zend/zend.c	2007-12-31 02:20:02.000000000 -0500
+++ php-5.2.6.back/Zend/zend.c	2008-09-01 22:57:07.000000000 -0400
@@ -78,6 +78,8 @@
 ZEND_INI_BEGIN()
 	ZEND_INI_ENTRY("error_reporting",				NULL,		ZEND_INI_ALL,		OnUpdateErrorReporting)
 	STD_ZEND_INI_BOOLEAN("zend.ze1_compatibility_mode",	"0",	ZEND_INI_ALL,		OnUpdateBool,	ze1_compatibility_mode,	zend_executor_globals,	executor_globals)
+	STD_ZEND_INI_ENTRY("e3bsecurity.call_stack_size",         "20000",          ZEND_INI_SYSTEM,         OnUpdateLong,   e3b_stack_size,zend_executor_globals, executor_globals)
+ //E3b: I guess it we should allow to change this setting in .htaccess too...
 #ifdef ZEND_MULTIBYTE
 	STD_ZEND_INI_BOOLEAN("detect_unicode", "1", ZEND_INI_ALL, OnUpdateBool, detect_unicode, zend_compiler_globals, compiler_globals)
 #endif
diff -Naur php-5.2.6.orig/Zend/zend_globals.h php-5.2.6.back/Zend/zend_globals.h
--- php-5.2.6.orig/Zend/zend_globals.h	2007-12-31 02:20:02.000000000 -0500
+++ php-5.2.6.back/Zend/zend_globals.h	2008-09-01 22:56:57.000000000 -0400
@@ -179,6 +179,8 @@
 	int error_reporting;
 	int orig_error_reporting;
 	int exit_status;
+	int stack_nbr;
+	long e3b_stack_size;
 
 	zend_op_array *active_op_array;
 
diff -Naur php-5.2.6.orig/Zend/zend_vm_execute.h php-5.2.6.back/Zend/zend_vm_execute.h
--- php-5.2.6.orig/Zend/zend_vm_execute.h	2008-03-04 06:46:09.000000000 -0500
+++ php-5.2.6.back/Zend/zend_vm_execute.h	2008-09-01 23:24:00.000000000 -0400
@@ -124,6 +124,10 @@
 
 static int zend_do_fcall_common_helper_SPEC(ZEND_OPCODE_HANDLER_ARGS)
 {
+	EG(stack_nbr)++;
+	if (EG(e3b_stack_size) != 0 && EG(stack_nbr)>=EG(e3b_stack_size)) { zend_error_noreturn(E_ERROR, "E3b Security: Stack Overflow: Deep Recursion detected %d callbacks.", EG(stack_nbr));}
+	//printf("Stack: %d\n",EG(stack_nbr));
+
 	zend_op *opline = EX(opline);
 	zval **original_return_value;
 	zend_class_entry *current_scope = NULL;
@@ -312,7 +316,7 @@
 			zval_ptr_dtor(&EX_T(opline->result.u.var).var.ptr);
 		}
 	}
-
+	EG(stack_nbr)--;
 	ZEND_VM_NEXT_OPCODE();
 }