diff --git a/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c b/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c
index cac442fc0..49ec48804 100644
--- a/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c
+++ b/src/libstrongswan/plugins/openssl/openssl_diffie_hellman.c
@@ -18,6 +18,7 @@
 
 #ifndef OPENSSL_NO_DH
 
+#include <openssl/bn.h>
 #include <openssl/dh.h>
 
 #include "openssl_diffie_hellman.h"
diff --git a/src/libstrongswan/plugins/openssl/openssl_ec_diffie_hellman.c b/src/libstrongswan/plugins/openssl/openssl_ec_diffie_hellman.c
index a1af500e2..11d6e8ec5 100644
--- a/src/libstrongswan/plugins/openssl/openssl_ec_diffie_hellman.c
+++ b/src/libstrongswan/plugins/openssl/openssl_ec_diffie_hellman.c
@@ -17,6 +17,7 @@
 
 #ifndef OPENSSL_NO_EC
 
+#include <openssl/bn.h>
 #include <openssl/ec.h>
 #include <openssl/objects.h>
 #include <openssl/bn.h>
diff --git a/src/libstrongswan/plugins/openssl/openssl_rsa_private_key.c b/src/libstrongswan/plugins/openssl/openssl_rsa_private_key.c
index 10a35c1fd..de02f302d 100644
--- a/src/libstrongswan/plugins/openssl/openssl_rsa_private_key.c
+++ b/src/libstrongswan/plugins/openssl/openssl_rsa_private_key.c
@@ -23,6 +23,7 @@
 
 #include <utils/debug.h>
 
+#include <openssl/bn.h>
 #include <openssl/evp.h>
 #include <openssl/rsa.h>
 #ifndef OPENSSL_NO_ENGINE
diff --git a/src/libstrongswan/plugins/openssl/openssl_rsa_public_key.c b/src/libstrongswan/plugins/openssl/openssl_rsa_public_key.c
index aa54d3bbd..db928569f 100644
--- a/src/libstrongswan/plugins/openssl/openssl_rsa_public_key.c
+++ b/src/libstrongswan/plugins/openssl/openssl_rsa_public_key.c
@@ -23,6 +23,7 @@
 
 #include <utils/debug.h>
 
+#include <openssl/bn.h>
 #include <openssl/evp.h>
 #include <openssl/rsa.h>
 #include <openssl/x509.h>
diff --git a/src/libstrongswan/plugins/openssl/openssl_util.c b/src/libstrongswan/plugins/openssl/openssl_util.c
index 0e61086b1..2f9813701 100644
--- a/src/libstrongswan/plugins/openssl/openssl_util.c
+++ b/src/libstrongswan/plugins/openssl/openssl_util.c
@@ -18,6 +18,7 @@
 
 #include <utils/debug.h>
 
+#include <openssl/bn.h>
 #include <openssl/evp.h>
 #include <openssl/x509.h>