diff --git a/code/graphics/opengl/gropengl.cpp b/code/graphics/opengl/gropengl.cpp
index 444515b797..73f1e100c8 100644
--- a/code/graphics/opengl/gropengl.cpp
+++ b/code/graphics/opengl/gropengl.cpp
@@ -956,7 +956,7 @@ void gr_opengl_use_viewport(os::Viewport* view) {
 
 int opengl_init_display_device()
 {
-	os::ViewPortProperties attrs;
+	os::ViewPortProperties attrs = {};
 	attrs.enable_opengl = true;
 
 	attrs.gl_attributes.major_version = MIN_REQUIRED_GL_VERSION / 10;
diff --git a/code/graphics/vulkan/VulkanDeferred.cpp b/code/graphics/vulkan/VulkanDeferred.cpp
index ef97b04c44..d4a4874434 100644
--- a/code/graphics/vulkan/VulkanDeferred.cpp
+++ b/code/graphics/vulkan/VulkanDeferred.cpp
@@ -271,6 +271,9 @@ void vulkan_deferred_lighting_begin(bool clearNonColorBufs)
 
 void vulkan_deferred_lighting_msaa()
 {
+	if (!Deferred_lighting) {
+		return;
+	}
 	if (Cmdline_msaa_enabled <= 0) {
 		return;
 	}
diff --git a/code/graphics/vulkan/VulkanRendererSetup.cpp b/code/graphics/vulkan/VulkanRendererSetup.cpp
index d338d55ee8..8fc0341e82 100644
--- a/code/graphics/vulkan/VulkanRendererSetup.cpp
+++ b/code/graphics/vulkan/VulkanRendererSetup.cpp
@@ -570,7 +570,7 @@ bool VulkanRenderer::initialize()
 
 bool VulkanRenderer::initDisplayDevice() const
 {
-	os::ViewPortProperties attrs;
+	os::ViewPortProperties attrs = {};
 	attrs.enable_opengl = false;
 	attrs.enable_vulkan = true;
 
diff --git a/code/osapi/DebugWindow.cpp b/code/osapi/DebugWindow.cpp
index 2619edd74f..120f329efa 100644
--- a/code/osapi/DebugWindow.cpp
+++ b/code/osapi/DebugWindow.cpp
@@ -39,7 +39,7 @@ SDL_DisplayID get_debug_display() {
 namespace osapi {
 
 DebugWindow::DebugWindow() {
-	os::ViewPortProperties attrs;
+	os::ViewPortProperties attrs = {};
 	uint32_t display = get_debug_display();
 	attrs.display = display;