diff --git a/opensc-0.20.0-lto-build.patch b/opensc-0.20.0-lto-build.patch
new file mode 100644
index 0000000..5028307
--- /dev/null
+++ b/opensc-0.20.0-lto-build.patch
@@ -0,0 +1,24 @@
+From 8551e84d74af24638581a473775b71e6aad10dcf Mon Sep 17 00:00:00 2001
+From: Frank Morgner <frankmorgner@gmail.com>
+Date: Wed, 4 Mar 2020 23:09:57 +0100
+Subject: [PATCH] fixed https://github.com/OpenSC/OpenSC/issues/1948
+
+closes https://github.com/OpenSC/OpenSC/pull/1958
+---
+ src/tests/p11test/p11test_case_pss_oaep.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/tests/p11test/p11test_case_pss_oaep.c b/src/tests/p11test/p11test_case_pss_oaep.c
+index 0194711924..b114b73658 100644
+--- a/src/tests/p11test/p11test_case_pss_oaep.c
++++ b/src/tests/p11test/p11test_case_pss_oaep.c
+@@ -376,7 +376,7 @@ int oaep_encrypt_decrypt_test(test_cert_t *o, token_info_t *info, test_mech_t *m
+ 	CK_BYTE *dec_message = NULL;
+ 	int dec_message_length = 0;
+ 	int message_length = 16;
+-	unsigned char *enc_message;
++	unsigned char *enc_message = NULL;
+ 	int enc_message_length, rv;
+ 
+ 	if (o->private_handle == CK_INVALID_HANDLE) {
+
diff --git a/opensc.spec b/opensc.spec
index e9baf20..6da3f3d 100644
--- a/opensc.spec
+++ b/opensc.spec
@@ -17,6 +17,8 @@ Patch1:         opensc-0.19.0-pinpad.patch
 Patch2:         opensc-0.20.0-no-common.patch
 # https://github.com/OpenSC/OpenSC/pull/1987
 Patch3:         opensc-0.20.0-cardos.patch
+# https://github.com/OpenSC/OpenSC/commit/8551e84d
+Patch4:         opensc-0.20.0-lto-build.patch
 
 BuildRequires:  pcsc-lite-devel
 BuildRequires:  readline-devel
@@ -53,6 +55,7 @@ every software/card that does so, too.
 %patch1 -p1 -b .pinpad
 %patch2 -p1 -b .no-common
 %patch3 -p1 -b .cardos
+%patch4 -p1 -b .lto-build
 
 cp %{SOURCE2} tests/
 # The test-pkcs11-tool-allowed-mechanisms already works in Fedora