diff --git a/tests/oss-fuzz/async_target.c b/tests/oss-fuzz/async_target.c
index 66fba4b7..3ea79c15 100644
--- a/tests/oss-fuzz/async_target.c
+++ b/tests/oss-fuzz/async_target.c
@@ -51,7 +51,8 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 
   coap_startup();
   coap_set_log_level(COAP_LOG_EMERG);
-  coap_debug_set_packet_loss("100%");
+  coap_debug_set_packet_loss("50%");
+  coap_debug_set_packet_fail("100%");
 
   ctx = coap_new_context(NULL);
   if (!ctx)
diff --git a/tests/oss-fuzz/network_message_target.c b/tests/oss-fuzz/network_message_target.c
index d0b29dec..0bb005b5 100644
--- a/tests/oss-fuzz/network_message_target.c
+++ b/tests/oss-fuzz/network_message_target.c
@@ -224,7 +224,8 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   /* Initialize CoAP library */
   coap_startup();
   coap_set_log_level(COAP_LOG_EMERG);
-  coap_debug_set_packet_loss("100%");
+  coap_debug_set_packet_loss("50%");
+  coap_debug_set_packet_fail("100%");
 
   /* Setup local address */
   coap_address_init(&local_addr);
diff --git a/tests/oss-fuzz/observe_target.c b/tests/oss-fuzz/observe_target.c
index ec69e35f..542d5a5c 100644
--- a/tests/oss-fuzz/observe_target.c
+++ b/tests/oss-fuzz/observe_target.c
@@ -20,7 +20,8 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 
   coap_startup();
   coap_set_log_level(COAP_LOG_EMERG);
-  coap_debug_set_packet_loss("100%");
+  coap_debug_set_packet_loss("50%");
+  coap_debug_set_packet_fail("100%");
 
   coap_context_t *ctx = coap_new_context(NULL);
   if (!ctx)
diff --git a/tests/oss-fuzz/oscore_decrypt_target.c b/tests/oss-fuzz/oscore_decrypt_target.c
index c6b50171..a08251ee 100644
--- a/tests/oss-fuzz/oscore_decrypt_target.c
+++ b/tests/oss-fuzz/oscore_decrypt_target.c
@@ -26,7 +26,8 @@ LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   coap_oscore_conf_t *oscore_conf = coap_new_oscore_conf(conf, NULL, NULL, 0);
 
   /* Stop transmission of any error packets */
-  coap_debug_set_packet_loss("1-10");
+  coap_debug_set_packet_loss("50%");
+  coap_debug_set_packet_fail("100%");
 
   /* Set up OSCORE context */
   ctx = coap_new_context(NULL);