diff --git a/emulators/virtualbox-ose/Makefile b/emulators/virtualbox-ose/Makefile
--- a/emulators/virtualbox-ose/Makefile
+++ b/emulators/virtualbox-ose/Makefile
@@ -217,17 +217,30 @@
 .endif
 
 .if ${CHOSEN_COMPILER_TYPE} == clang
-# llvm10 in FreeBSD before r364284 miscompiles virtualbox 6.1 causing errors.
-# force llvm11 from ports
+# 1) llvm10 in FreeBSD before r364284 miscompiles virtualbox 6.1 causing errors.
+# 2) llvm15 in FreeBSD miscompiles virtualbox 6.1 causing errors: PR#270189.
+# Force llvm from ports.
 .if ${OPSYS} == FreeBSD && \
-    (${OSVERSION} < 1203502 || ${OSVERSION} >= 1300000 && ${OSVERSION} < 1300109)
+    (${OSVERSION} < 1203502 || ${OSVERSION} >= 1300000 && ${OSVERSION} < 1300109 || \
+    ${OSVERSION} >= 1302505 && ${OSVERSION} < 1400000 || ${OSVERSION} >= 1400079)
+# USES must be before .include <bsd.port.pre.mk>, but CHOSEN_COMPILER_TYPE must be after.
+# This is a workaround with possibility to define different llvm via VBOX_LLVM_VER in make.conf.
+#USES+=		llvm:min=11,max=14
+#CC=		clang${LLVM_VERSION}
+#CXX=		clang++${LLVM_VERSION}
 BUILD_DEPENDS+=	clang${VBOX_LLVM_VER}:devel/llvm${VBOX_LLVM_VER}
 CC=		clang${VBOX_LLVM_VER}
 CXX=		clang++${VBOX_LLVM_VER}
-VBOX_LLVM_VER?=	11
+.if ${LLVM_DEFAULT} < 11 || ${LLVM_DEFAULT} > 14
+VBOX_LLVM_VER?=	14
+.else
+VBOX_LLVM_VER?=	${LLVM_DEFAULT}
+.endif
 .endif
 PATCH_DEPENDS+=	${LOCALBASE}/share/kBuild/tools/GXX3.kmk:devel/kBuild
 EXTRA_PATCHES+=	${PATCHDIR}/extrapatch-src-VBox-Devices-PC-ipxe-Makefile.kmk
+EXTRA_PATCHES+=	${PATCHDIR}/extrapatch-src_VBox_Devices_PC_ipxe_src_core_settings.c
+EXTRA_PATCHES+=	${PATCHDIR}/extrapatch-src_VBox_Devices_PC_ipxe_src_net_tcp_httpcore.c
 .endif
 
 .if ${PYTHON_MAJOR_VER} >= 3
diff --git a/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_ipxe_src_core_settings.c b/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_ipxe_src_core_settings.c
new file mode 100644
--- /dev/null
+++ b/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_ipxe_src_core_settings.c
@@ -0,0 +1,11 @@
+--- src/VBox/Devices/PC/ipxe/src/core/settings.c.orig
++++ src/VBox/Devices/PC/ipxe/src/core/settings.c
+@@ -286,7 +286,7 @@
+ 						     const char *name ) {
+ 	struct {
+ 		struct autovivified_settings autovivified;
+-		char name[ strlen ( name ) + 1 /* NUL */ ];
++		char name[ 32 ];
+ 	} *new_child;
+ 	struct settings *settings;
+ 
diff --git a/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_ipxe_src_net_tcp_httpcore.c b/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_ipxe_src_net_tcp_httpcore.c
new file mode 100644
--- /dev/null
+++ b/emulators/virtualbox-ose/files/extrapatch-src_VBox_Devices_PC_ipxe_src_net_tcp_httpcore.c
@@ -0,0 +1,15 @@
+--- src/VBox/Devices/PC/ipxe/src/net/tcp/httpcore.c.orig
++++ src/VBox/Devices/PC/ipxe/src/net/tcp/httpcore.c
+@@ -646,9 +646,9 @@
+ 	int request_len = unparse_uri ( NULL, 0, http->uri,
+ 					URI_PATH_BIT | URI_QUERY_BIT );
+ 	struct {
+-		uint8_t user_pw[ user_pw_len + 1 /* NUL */ ];
+-		char user_pw_base64[ user_pw_base64_len + 1 /* NUL */ ];
+-		char request[ request_len + 1 /* NUL */ ];
++		uint8_t user_pw[ 32 ];
++		char user_pw_base64[ 64 ];
++		char request[ 1024 ];
+ 		char range[48]; /* Enough for two 64-bit integers in decimal */
+ 	} *dynamic;
+ 	int partial;