diff --git a/ChangeLog b/ChangeLog
index 0a98d67397616c441a0d4fbd8aaa7052151ed85b..ca7d7bf7dae8610a3752e69454485bcedb292923 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,17 +1,19 @@
 2023-11-15  Niels Möller  <nisse@lysator.liu.se>
 
+	* ecc-mod-arith.c (ecc_mod_addmul_1): Use assert_maybe.
+	* ecc-curve448.c (ecc_curve448_modp): Likewise.
+
 	* testsuite/curve25519-dh-test.c (test_g): Add calls to
 	mark_bytes_undefined and mark_bytes_defined.
 	(test_a): Likewise.
 	(test_main): Skip side-channel tests in builds with mini-gmp or
 	extra asserts enabled.
-
-	* ecc-mod-arith.c (ecc_mod_addmul_1): Use assert_maybe.
+	* testsuite/curve448-dh-test.c: Analogous changes.
 
 	* testsuite/Makefile.in (TS_SC_HOGWEED): New make variable. Added
-	sc-curve25519-dh-test to list.
-
+	sc-curve25519-dh-test and sc-curve448-dh-test to list.
 	* testsuite/sc-curve25519-dh-test: New testcase.
+	* testsuite/sc-curve448-dh-test: New testcase.
 
 2023-11-14  Niels Möller  <nisse@lysator.liu.se>
 
diff --git a/ecc-curve448.c b/ecc-curve448.c
index daef56cc83654ddf084012194c30cb9916681eba..1bffeeb7cb323795c83c0f9d31ebe14020917821 100644
--- a/ecc-curve448.c
+++ b/ecc-curve448.c
@@ -91,7 +91,7 @@ ecc_curve448_modp(const struct ecc_modulo *m, mp_limb_t *rp, mp_limb_t *xp)
   tp[5] = tp[6] = 0;
   c7 = mpn_add_n (rp, xp, tp, 7);
   c7 = mpn_cnd_add_n (c7, rp, rp, m->B, 7);
-  assert (c7 == 0);
+  assert_maybe (c7 == 0);
 }
 #else
 #define ecc_curve448_modp ecc_mod
diff --git a/testsuite/Makefile.in b/testsuite/Makefile.in
index b8bce5564799669b0898876edf542c849f9bdb17..cf3d962cb108399f4ecb9513ba274ee19537eaf8 100644
--- a/testsuite/Makefile.in
+++ b/testsuite/Makefile.in
@@ -67,7 +67,7 @@ TS_C = $(TS_NETTLE) @IF_HOGWEED@ $(TS_HOGWEED)
 TS_CXX = @IF_CXX@ $(CXX_SOURCES:.cxx=$(EXEEXT))
 TARGETS = $(TS_C) $(TS_CXX)
 TS_SC_HOGWEED = sc-pkcs1-sec-decrypt-test sc-rsa-sec-decrypt-test \
-	sc-ecdsa-sign-test sc-curve25519-dh-test
+	sc-ecdsa-sign-test sc-curve25519-dh-test sc-curve448-dh-test
 TS_SC = sc-cnd-memcpy-test sc-gcm-test sc-memeql-test \
 	@IF_HOGWEED@ $(TS_SC_HOGWEED)
 
diff --git a/testsuite/curve448-dh-test.c b/testsuite/curve448-dh-test.c
index 7d142d6f350b789bb1b96f8439210f5cb627fb54..c91a57532335e321e6d257564cc843361b598983 100644
--- a/testsuite/curve448-dh-test.c
+++ b/testsuite/curve448-dh-test.c
@@ -38,7 +38,10 @@ static void
 test_g (const uint8_t *s, const uint8_t *r)
 {
   uint8_t p[CURVE448_SIZE];
+  mark_bytes_undefined (CURVE448_SIZE, s);
   curve448_mul_g (p, s);
+  mark_bytes_defined (CURVE448_SIZE, p);
+
   if (!MEMEQ (CURVE448_SIZE, p, r))
     {
       printf ("curve448_mul_g failure:\ns = ");
@@ -56,7 +59,11 @@ static void
 test_a (const uint8_t *s, const uint8_t *b, const uint8_t *r)
 {
   uint8_t p[CURVE448_SIZE];
+  mark_bytes_undefined (CURVE448_SIZE, s);
+  mark_bytes_undefined (CURVE448_SIZE, b);
   curve448_mul (p, s, b);
+  mark_bytes_defined (CURVE448_SIZE, p);
+
   if (!MEMEQ (CURVE448_SIZE, p, r))
     {
       printf ("curve448_mul failure:\ns = ");
@@ -75,6 +82,10 @@ test_a (const uint8_t *s, const uint8_t *b, const uint8_t *r)
 void
 test_main (void)
 {
+#if NETTLE_USE_MINI_GMP || WITH_EXTRA_ASSERTS
+  if (test_side_channel)
+    SKIP();
+#endif
   /* From RFC 7748. */
   test_g (H("9a8f4925d1519f5775cf46b04b5800d4ee9ee8bae8bc5565d498c28d"
 	    "d9c9baf574a9419744897391006382a6f127ab1d9ac2d8c0a598726b"),
diff --git a/testsuite/sc-curve448-dh-test b/testsuite/sc-curve448-dh-test
new file mode 100755
index 0000000000000000000000000000000000000000..fdd59bdc514ea2eb95a08fe7d8c3df9129d6acc9
--- /dev/null
+++ b/testsuite/sc-curve448-dh-test
@@ -0,0 +1,6 @@
+#! /bin/sh
+
+srcdir=`dirname $0`
+. "${srcdir}/sc-valgrind.sh"
+
+with_valgrind ./curve448-dh-test