@@ -, +, @@ 
 --enable-autoexec|-y|-666  (CVE-2009-3850)
 source/blender/blenkernel/intern/blender.c     |    3 ++-
 source/blender/makesrna/intern/rna_userdef.c   |    9 ++++++---
 source/blender/windowmanager/intern/wm_files.c |    3 ++-
 source/creator/creator.c                       |   10 ++++++----
 4 files changed, 16 insertions(+), 9 deletions(-)
--- a/source/blender/blenkernel/intern/blender.c	
+++ a/source/blender/blenkernel/intern/blender.c	
@@ -141,7 +141,8 @@ void initglobals(void)
 	G.charmin = 0x0000;
 	G.charmax = 0xffff;
 	
-	G.f |= G_SCRIPT_AUTOEXEC;
+	G.f &= ~G_SCRIPT_AUTOEXEC;
+	G.f |= G_SCRIPT_OVERRIDE_PREF;  /* Disables turning G_SCRIPT_AUTOEXEC on from user prefs */
 }
 
 /***/
--- a/source/blender/makesrna/intern/rna_userdef.c	
+++ a/source/blender/makesrna/intern/rna_userdef.c	
@@ -99,9 +99,12 @@ static void rna_userdef_show_manipulator_update(Main *bmain, Scene *scene, Point
 
 static void rna_userdef_script_autoexec_update(Main *bmain, Scene *scene, PointerRNA *ptr)
 {
-	UserDef *userdef = (UserDef*)ptr->data;
-	if (userdef->flag & USER_SCRIPT_AUTOEXEC_DISABLE)	G.f &= ~G_SCRIPT_AUTOEXEC;
-	else												G.f |=  G_SCRIPT_AUTOEXEC;
+	if ((G.f & G_SCRIPT_OVERRIDE_PREF) == 0) {
+		/* Blender run with --enable-autoexec */
+		UserDef *userdef = (UserDef*)ptr->data;
+		if (userdef->flag & USER_SCRIPT_AUTOEXEC_DISABLE)	G.f &= ~G_SCRIPT_AUTOEXEC;
+		else												G.f |=  G_SCRIPT_AUTOEXEC;
+	}
 }
 
 static void rna_userdef_mipmap_update(Main *bmain, Scene *scene, PointerRNA *ptr)
--- a/source/blender/windowmanager/intern/wm_files.c	
+++ a/source/blender/windowmanager/intern/wm_files.c	
@@ -270,7 +270,8 @@ static void wm_init_userdef(bContext *C)
 
 	/* set the python auto-execute setting from user prefs */
 	/* enabled by default, unless explicitly enabled in the command line which overrides */
-	if((G.f & G_SCRIPT_OVERRIDE_PREF) == 0) {
+	if (! G.background && ((G.f & G_SCRIPT_OVERRIDE_PREF) == 0)) {
+		/* Blender run with --enable-autoexec */
 		if ((U.flag & USER_SCRIPT_AUTOEXEC_DISABLE) == 0) G.f |=  G_SCRIPT_AUTOEXEC;
 		else											  G.f &= ~G_SCRIPT_AUTOEXEC;
 	}
--- a/source/creator/creator.c	
+++ a/source/creator/creator.c	
@@ -278,6 +278,7 @@ static int print_help(int UNUSED(argc), const char **UNUSED(argv), void *data)
 
 	printf("\n");
 
+	BLI_argsPrintArgDoc(ba, "-666");
 	BLI_argsPrintArgDoc(ba, "--enable-autoexec");
 	BLI_argsPrintArgDoc(ba, "--disable-autoexec");
 
@@ -359,14 +360,14 @@ static int end_arguments(int UNUSED(argc), const char **UNUSED(argv), void *UNUS
 static int enable_python(int UNUSED(argc), const char **UNUSED(argv), void *UNUSED(data))
 {
 	G.f |= G_SCRIPT_AUTOEXEC;
-	G.f |= G_SCRIPT_OVERRIDE_PREF;
+	G.f &= ~G_SCRIPT_OVERRIDE_PREF;  /* Enables turning G_SCRIPT_AUTOEXEC off from user prefs */
 	return 0;
 }
 
 static int disable_python(int UNUSED(argc), const char **UNUSED(argv), void *UNUSED(data))
 {
 	G.f &= ~G_SCRIPT_AUTOEXEC;
-	G.f |= G_SCRIPT_OVERRIDE_PREF;
+	G.f |= G_SCRIPT_OVERRIDE_PREF;  /* Disables turning G_SCRIPT_AUTOEXEC on from user prefs */
 	return 0;
 }
 
@@ -1075,8 +1076,9 @@ static void setupArguments(bContext *C, bArgs *ba, SYS_SystemHandle *syshandle)
 
 	BLI_argsAdd(ba, 1, "-v", "--version", "\n\tPrint Blender version and exit", print_version, NULL);
 
-	BLI_argsAdd(ba, 1, "-y", "--enable-autoexec", "\n\tEnable automatic python script execution (default)", enable_python, NULL);
-	BLI_argsAdd(ba, 1, "-Y", "--disable-autoexec", "\n\tDisable automatic python script execution (pydrivers, pyconstraints, pynodes)", disable_python, NULL);
+	BLI_argsAdd(ba, 1, NULL, "-666", "\n\tEnable automatic python script execution (port from CVE-2009-3850 patch to Blender 2.49b)", enable_python, NULL);
+	BLI_argsAdd(ba, 1, "-y", "--enable-autoexec", "\n\tEnable automatic python script execution", enable_python, NULL);
+	BLI_argsAdd(ba, 1, "-Y", "--disable-autoexec", "\n\tDisable automatic python script execution (pydrivers, pyconstraints, pynodes) (default)", disable_python, NULL);
 
 	BLI_argsAdd(ba, 1, "-b", "--background", "<file>\n\tLoad <file> in background (often used for UI-less rendering)", background_mode, NULL);