diff --git a/tests/subsys/secure_storage/psa/crypto/overlay-secure_storage.conf b/tests/subsys/secure_storage/psa/crypto/overlay-secure_storage.conf
index 063c04fd2b5e..e076008277b6 100644
--- a/tests/subsys/secure_storage/psa/crypto/overlay-secure_storage.conf
+++ b/tests/subsys/secure_storage/psa/crypto/overlay-secure_storage.conf
@@ -4,6 +4,8 @@ CONFIG_MAIN_STACK_SIZE=2048
 CONFIG_MBEDTLS=y
 CONFIG_TEST_RANDOM_GENERATOR=y
 CONFIG_TIMER_RANDOM_GENERATOR=y
+# PSA Crypto needs some heap, but MINIMAL_LIBC has none by default.
+CONFIG_COMMON_LIBC_MALLOC_ARENA_SIZE=2048
 CONFIG_MBEDTLS_PSA_CRYPTO_C=y
 
 CONFIG_SECURE_STORAGE=y
diff --git a/tests/subsys/secure_storage/psa/its/overlay-default_transform.conf b/tests/subsys/secure_storage/psa/its/overlay-default_transform.conf
index 2f49f5d6593a..dd3041073096 100644
--- a/tests/subsys/secure_storage/psa/its/overlay-default_transform.conf
+++ b/tests/subsys/secure_storage/psa/its/overlay-default_transform.conf
@@ -1,6 +1,8 @@
 CONFIG_MBEDTLS=y
 CONFIG_TEST_RANDOM_GENERATOR=y
 CONFIG_TIMER_RANDOM_GENERATOR=y
+# PSA Crypto needs some heap, but MINIMAL_LIBC has none by default.
+CONFIG_COMMON_LIBC_MALLOC_ARENA_SIZE=2048
 CONFIG_MBEDTLS_PSA_CRYPTO_C=y
 
 # SETTINGS_MAX_VAL_LEN (256) - flags (1) - CONFIG_SECURE_STORAGE_ITS_TRANSFORM_OUTPUT_OVERHEAD (28)