diff --git a/devel/compdbgen/Makefile b/devel/compdbgen/Makefile
index 9d4717eedd7e..fad3099fd807 100644
--- a/devel/compdbgen/Makefile
+++ b/devel/compdbgen/Makefile
@@ -1,25 +1,31 @@
 PORTNAME=	compdbgen
 DISTVERSION=	g20250911
 CATEGORIES=	devel
 
 MAINTAINER=	jrm@FreeBSD.org
 COMMENT=	General-purpose tool for generating compile_commands.json files
 WWW=		https://github.com/Virus-V/compdbgen
 
 LICENSE=	BSD2CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	Virus-V
 GH_TAGNAME=	726a5c1d9b94650ced9dc13044e9459bc8780364
 GH_TUPLE=	DaveGamble:cJSON:c859b25da02955fef659d658b8f324b5cde87be3:cJSONS/cjson
 
 PLIST_FILES=	bin/${PORTNAME}
 
 do-build:
 		@cd ${WRKSRC}/ && ${SH} ./build.sh
 
 do-install:
 		${INSTALL_PROGRAM} ${WRKSRC}/${PORTNAME} ${STAGEDIR}${PREFIX}/bin
 
+.include <bsd.port.options.mk>
+
+.if ${OPSYS} == FreeBSD && ${OSVERSION} < 1400000
+EXTRA_PATCHES=	${PATCHDIR}/extra-patch-mainloop.c
+.endif
+
 .include <bsd.port.mk>
diff --git a/devel/compdbgen/files/extra-patch-mainloop.c b/devel/compdbgen/files/extra-patch-mainloop.c
new file mode 100644
index 000000000000..33a01eecebac
--- /dev/null
+++ b/devel/compdbgen/files/extra-patch-mainloop.c
@@ -0,0 +1,35 @@
+--- mainloop.c.orig	2025-09-11 04:56:11 UTC
++++ mainloop.c
+@@ -433,20 +433,32 @@ static void enter_syscall(struct glbctx *info, struct 
+   static int json_item_cnt = 0;
+   struct syscall *sc;
+   u_int i, narg;
++#if defined(__FreeBSD_version) && __FreeBSD_version < 1400000
++  register_t *args;
++#else
+   syscallarg_t *args;
++#endif
+ 
+   /* ignore other syscall except execve */
+   if (pl->pl_syscall_code != SYS_execve) {
+     return;
+   }
+ 
++#if defined(__FreeBSD_version) && __FreeBSD_version < 1400000
++  args = calloc(pl->pl_syscall_narg, sizeof(register_t));
++#else
+   args = calloc(pl->pl_syscall_narg, sizeof(syscallarg_t));
++#endif
+   if (args == NULL) {
+     err(1, "malloc syscall args failed\n");
+   }
+ 
+   if (ptrace(PT_GET_SC_ARGS, t->tid, (caddr_t)args,
++#if defined(__FreeBSD_version) && __FreeBSD_version < 1400000
++             sizeof(register_t) * pl->pl_syscall_narg) != 0) {
++#else
+              sizeof(syscallarg_t) * pl->pl_syscall_narg) != 0) {
++#endif
+     goto _EXIT;
+   }
+