diff --git a/lib/libpam/modules/pam_rhosts/pam_rhosts.c b/lib/libpam/modules/pam_rhosts/pam_rhosts.c
index 1060fc5a97c9..ab4222494a15 100644
--- a/lib/libpam/modules/pam_rhosts/pam_rhosts.c
+++ b/lib/libpam/modules/pam_rhosts/pam_rhosts.c
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 
 #include <pwd.h>
 #include <stddef.h>
+#include <string.h>
 #include <unistd.h>
 
 #define PAM_SM_AUTH