diff --git a/configure.sh b/configure.sh
index 4f945292..bd09e9fa 100755
--- a/configure.sh
+++ b/configure.sh
@@ -949,7 +949,7 @@ if [ "$karatsuba_len" -lt 16 ]; then
 fi
 
 if [ "$ossfuzz" -ne 0 ] && [ "$memcheck" -eq 0 ]; then
-	usage "Can only enable OSSFUZZ when MEMCHECK is enabled"
+	memcheck=1
 fi
 
 set -e
@@ -1180,6 +1180,8 @@ if [ "$fuzz" -ne 0 ] || [ "$ossfuzz" -ne 0 ]; then
 	hist=0
 	nls=0
 	optimization="3"
+	bc_default_expr_exit=0
+	dc_default_expr_exit=0
 fi
 
 # This sets some necessary things for debug mode.
diff --git a/src/bc_fuzzer.c b/src/bc_fuzzer.c
index cd00a25b..54d7104e 100644
--- a/src/bc_fuzzer.c
+++ b/src/bc_fuzzer.c
@@ -104,6 +104,7 @@ LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size)
 exit:
 
 	BC_SIG_MAYLOCK;
+	s = bc_vm_atexit(s);
 
 	free(bc_fuzzer_data);
 
diff --git a/src/dc_fuzzer.c b/src/dc_fuzzer.c
index 7e3e7df5..5bbf24a5 100644
--- a/src/dc_fuzzer.c
+++ b/src/dc_fuzzer.c
@@ -104,6 +104,7 @@ LLVMFuzzerTestOneInput(const uint8_t* Data, size_t Size)
 exit:
 
 	BC_SIG_MAYLOCK;
+	s = bc_vm_atexit(s);
 
 	free(bc_fuzzer_data);