diff --git a/repos/ports/src/virtualbox5/frontend/console.cc b/repos/ports/src/virtualbox5/frontend/console.cc
index 2344f15fa..23a01de29 100644
--- a/repos/ports/src/virtualbox5/frontend/console.cc
+++ b/repos/ports/src/virtualbox5/frontend/console.cc
@@ -12,6 +12,7 @@
  */
 
 #include <base/log.h>
+#include <libc/component.h>
 #include <util/xml_node.h>
 
 #include <VBox/settings.h>
@@ -123,7 +124,7 @@ void GenodeConsole::update_video_mode()
 	                    32);
 }
 
-void GenodeConsole::handle_input()
+void GenodeConsole::_handle_input()
 {
 	/* disable input processing if vm is powered down */
 	if (vm_down && (_vbox_mouse || _vbox_keyboard)) {
@@ -273,7 +274,7 @@ void GenodeConsole::handle_input()
 		                                RTTimeMilliTS());
 }
 
-void GenodeConsole::handle_mode_change()
+void GenodeConsole::_handle_mode_change()
 {
 	IFramebuffer *pFramebuffer = NULL;
 	HRESULT rc = i_getDisplay()->QueryFramebuffer(0, &pFramebuffer);
@@ -312,7 +313,7 @@ void GenodeConsole::init_clipboard()
 	}
 }
 
-void GenodeConsole::handle_cb_rom_change()
+void GenodeConsole::_handle_cb_rom_change()
 {
 	if (!_clipboard_rom)
 		return;
@@ -332,7 +333,7 @@ void GenodeConsole::init_backends(IKeyboard * gKeyboard, IMouse * gMouse)
 
 	_nitpicker.mode_sigh(_mode_change_signal_dispatcher);
 
-	handle_mode_change();
+	_handle_mode_change();
 }
 
 void GenodeConsole::i_onMouseCapabilityChange(BOOL supportsAbsolute,
@@ -518,7 +519,7 @@ void fireKeyboardLedsChangedEvent(IEventSource *, bool num_lock,
 	guest_caps_lock = caps_lock;
 }
 
-void GenodeConsole::handle_sticky_keys()
+void GenodeConsole::_handle_sticky_keys()
 {
 	/* no keyboard - no sticky key handling */
 	if (!_vbox_keyboard || !_caps_lock.constructed())
@@ -553,3 +554,15 @@ void GenodeConsole::handle_sticky_keys()
 		_vbox_keyboard->PutScancode(Input::KEY_CAPSLOCK | 0x80);
 	}
 }
+
+void GenodeConsole::handle_input() {
+	Libc::with_libc([&] () { _handle_input(); }); }
+
+void GenodeConsole::handle_sticky_keys() {
+	Libc::with_libc([&] () { _handle_sticky_keys(); }); }
+
+void GenodeConsole::handle_mode_change() {
+	Libc::with_libc([&] () { _handle_mode_change(); }); }
+
+void GenodeConsole::handle_cb_rom_change() {
+	Libc::with_libc([&] () { _handle_cb_rom_change(); }); }
diff --git a/repos/ports/src/virtualbox5/frontend/console.h b/repos/ports/src/virtualbox5/frontend/console.h
index a8e5917b8..ddcbcca92 100644
--- a/repos/ports/src/virtualbox5/frontend/console.h
+++ b/repos/ports/src/virtualbox5/frontend/console.h
@@ -140,6 +140,11 @@ class GenodeConsole : public Console {
 			    || keycode == Input::BTN_MIDDLE;
 		}
 
+		void _handle_input();
+		void _handle_mode_change();
+		void _handle_cb_rom_change();
+		void _handle_sticky_keys();
+
 	public:
 
 		GenodeConsole()
diff --git a/repos/ports/src/virtualbox5/generic/sup_vmm.cc b/repos/ports/src/virtualbox5/generic/sup_vmm.cc
index 703b885ff..dfe9d8d05 100644
--- a/repos/ports/src/virtualbox5/generic/sup_vmm.cc
+++ b/repos/ports/src/virtualbox5/generic/sup_vmm.cc
@@ -1154,8 +1154,10 @@ class Periodic_gip
 			ASMAtomicIncU32(&cpu->u32TransactionId);
 
 			/* call the timer function of the RTTimerCreate call */
-			if (rttimer_func)
-				rttimer_func(nullptr, rttimer_obj, 0);
+			if (rttimer_func) {
+				Libc::with_libc([&] () {
+					rttimer_func(nullptr, rttimer_obj, 0); });
+			}
 
 			for (Vcpu_handler *vcpu_handler = vcpu_handler_list().first();
 			     vcpu_handler;
diff --git a/repos/ports/src/virtualbox5/network.cpp b/repos/ports/src/virtualbox5/network.cpp
index 8d6cc2d3c..f743e6410 100644
--- a/repos/ports/src/virtualbox5/network.cpp
+++ b/repos/ports/src/virtualbox5/network.cpp
@@ -45,6 +45,7 @@
 
 /* VBox Genode specific */
 #include "vmm.h"
+#include <libc/component.h>
 
 /*******************************************************************************
 *   Structures and Typedefs                                                    *
@@ -121,12 +122,13 @@ class Nic_client
 
 				char *rx_content = _nic.rx()->packet_content(rx_packet);
 
-				int rc = _down_rx->pfnWaitReceiveAvail(_down_rx, RT_INDEFINITE_WAIT);
-				if (RT_FAILURE(rc))
-					continue;
+				Libc::with_libc([&] () {
+					int rc = _down_rx->pfnWaitReceiveAvail(_down_rx, RT_INDEFINITE_WAIT);
+					if (RT_FAILURE(rc)) return;
 
-				rc = _down_rx->pfnReceive(_down_rx, rx_content, rx_packet.size());
-				AssertRC(rc);
+					rc = _down_rx->pfnReceive(_down_rx, rx_content, rx_packet.size());
+					AssertRC(rc);
+				});
 
 				_nic.rx()->acknowledge_packet(rx_packet);
 			}
@@ -138,9 +140,11 @@ class Nic_client
 		{
 			_link_up = _nic.link_state();
 
-			_down_rx_config->pfnSetLinkState(_down_rx_config,
-			                                 _link_up ? PDMNETWORKLINKSTATE_UP
-			                                          : PDMNETWORKLINKSTATE_DOWN);
+			Libc::with_libc([&] () {
+				_down_rx_config->pfnSetLinkState(_down_rx_config,
+				                                 _link_up ? PDMNETWORKLINKSTATE_UP
+				                                          : PDMNETWORKLINKSTATE_DOWN);
+			});
 		}
 
 		void _handle_destruct()