diff --git a/libica-sles15sp2-x25519-x448-fix-handling-of-non-canonical-values.patch b/libica-sles15sp2-x25519-x448-fix-handling-of-non-canonical-values.patch
new file mode 100644
index 0000000..47298b7
--- /dev/null
+++ b/libica-sles15sp2-x25519-x448-fix-handling-of-non-canonical-values.patch
@@ -0,0 +1,131 @@
+From a3b36ef136e304a1e2dc12ef7b96686202cbd00d Mon Sep 17 00:00:00 2001
+From: Patrick Steuer <patrick.steuer@de.ibm.com>
+Date: Wed, 13 Nov 2019 17:12:43 +0100
+Subject: [PATCH] x25519,x448: fix handling of non-canonical values
+
+Reduce the peer public key's u-coordinate if it is >= p.
+
+Signed-off-by: Patrick Steuer <patrick.steuer@de.ibm.com>
+---
+ src/s390_ecc.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 91 insertions(+)
+
+diff --git a/src/s390_ecc.c b/src/s390_ecc.c
+index 7654959..62799ee 100644
+--- a/src/s390_ecc.c
++++ b/src/s390_ecc.c
+@@ -557,6 +557,91 @@ struct {				\
+ 	return rc;
+ }
+ 
++/*
++ * mask must be 0xFF or 0x00.
++ * "constant time" is per len.
++ *
++ * if (mask) {
++ *     unsigned char tmp[len];
++ *
++ *     memcpy(tmp, a, len);
++ *     memcpy(a, b);
++ *     memcpy(b, tmp);
++ * }
++ */
++static inline void constant_time_cond_swap_buff(unsigned char mask,
++						unsigned char *a,
++						unsigned char *b,
++						size_t len)
++{
++	size_t i;
++	unsigned char tmp;
++
++	for (i = 0; i < len; i++) {
++		tmp = a[i] ^ b[i];
++		tmp &= mask;
++		a[i] ^= tmp;
++		b[i] ^= tmp;
++	}
++}
++
++
++static void s390_x25519_mod_p(unsigned char u[32])
++{
++	unsigned char u_red[32];
++	unsigned int c = 0;
++	int i;
++
++	memcpy(u_red, u, sizeof(u_red));
++
++	c += (unsigned int)u_red[31] + 19;
++	u_red[31] = (unsigned char)c;
++	c >>= 8;
++
++	for (i = 30; i >= 0; i--) {
++		c += (unsigned int)u_red[i];
++		u_red[i] = (unsigned char)c;
++		c >>= 8;
++	}
++
++	c = (u_red[0] & 0x80) >> 7;
++	u_red[0] &= 0x7f;
++	constant_time_cond_swap_buff(0 - (unsigned char)c,
++				     u, u_red, sizeof(u_red));
++}
++
++static void s390_x448_mod_p(unsigned char u[56])
++{
++	unsigned char u_red[56];
++	unsigned int c = 0;
++	int i;
++
++	memcpy(u_red, u, sizeof(u_red));
++
++	c += (unsigned int)u_red[55] + 1;
++	u_red[55] = (unsigned char)c;
++	c >>= 8;
++
++	for (i = 54; i >= 28; i--) {
++		c += (unsigned int)u_red[i];
++		u_red[i] = (unsigned char)c;
++		c >>= 8;
++	}
++
++	c += (unsigned int)u_red[27] + 1;
++	u_red[27] = (unsigned char)c;
++	c >>= 8;
++
++	for (i = 26; i >= 0; i--) {
++		c += (unsigned int)u_red[i];
++		u_red[i] = (unsigned char)c;
++		c >>= 8;
++	}
++
++	constant_time_cond_swap_buff(0 - (unsigned char)c,
++				     u, u_red, sizeof(u_red));
++}
++
+ int scalar_mulx_cpacf(unsigned char *res_u,
+ 		      const unsigned char *scalar,
+ 		      const unsigned char *u,
+@@ -598,6 +683,9 @@ struct {				\
+ 		s390_flip_endian_32(param.X25519.u, param.X25519.u);
+ 		s390_flip_endian_32(param.X25519.scalar, param.X25519.scalar);
+ 
++		/* reduce non-canonical values */
++		s390_x25519_mod_p(param.X25519.u);
++
+ 		fc = s390_pcc_functions[SCALAR_MULTIPLY_X25519].hw_fc;
+ 		rc = s390_pcc(fc, &param) ? EIO : 0;
+ 
+@@ -619,6 +707,9 @@ struct {				\
+ 		s390_flip_endian_64(param.X448.u, param.X448.u);
+ 		s390_flip_endian_64(param.X448.scalar, param.X448.scalar);
+ 
++		/* reduce non-canonical values */
++		s390_x448_mod_p(param.X448.u + 8);
++
+ 		fc = s390_pcc_functions[SCALAR_MULTIPLY_X448].hw_fc;
+ 		rc = s390_pcc(fc, &param) ? EIO : 0;
+ 
+-- 
+2.13.7
+
diff --git a/libica.changes b/libica.changes
index 51362b1..ac7f105 100644
--- a/libica.changes
+++ b/libica.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Thu Nov 14 22:45:16 UTC 2019 - Mark Post <mpost@suse.com>
+
+- Added libica-sles15sp2-x25519-x448-fix-handling-of-non-canonical-values.patch
+  (bsc#1156768)
+
 -------------------------------------------------------------------
 Tue Oct 15 18:53:36 UTC 2019 - Mark Post <mpost@suse.com>
 
diff --git a/libica.spec b/libica.spec
index 5d45c5b..71a360c 100644
--- a/libica.spec
+++ b/libica.spec
@@ -37,6 +37,7 @@ Source4:        z90crypt
 Source5:        z90crypt.service
 Source6:        baselibs.conf
 Source7:        %{name}-rpmlintrc
+Patch1:         libica-sles15sp2-x25519-x448-fix-handling-of-non-canonical-values.patch
 BuildRequires:  autoconf
 BuildRequires:  automake
 BuildRequires:  gcc-c++