diff --git a/sys/conf/options b/sys/conf/options
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -1021,3 +1021,11 @@
 IICHID_SAMPLING	opt_hid.h
 HKBD_DFLT_KEYMAP	opt_hkbd.h
 HIDRAW_MAKE_UHID_ALIAS	opt_hid.h
+
+# kenv options
+# The early kernel environment (loader environment, config(8)-provided static)
+# is typically cleared after the dynamic environment comes up to ensure that
+# we're not inadvertently holding on to 'secret' values in these stale envs.
+# This option is insecure except in controlled environments where the static
+# environment's contents are known to be safe.
+PRESERVE_EARLY_KENV	opt_global.h
diff --git a/sys/kern/kern_environment.c b/sys/kern/kern_environment.c
--- a/sys/kern/kern_environment.c
+++ b/sys/kern/kern_environment.c
@@ -365,7 +365,11 @@
 			kenvp[i] = malloc(len, M_KENV, M_WAITOK);
 			strcpy(kenvp[i++], cp);
 sanitize:
+#ifdef PRESERVE_EARLY_KENV
+			continue;
+#else
 			explicit_bzero(cp, len - 1);
+#endif
 		}
 		*curpos = i;
 	}