diff --git a/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp b/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
index 99a7906d..f88518ec 100644
--- a/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
+++ b/libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp
@@ -579,20 +579,24 @@ TEST_F(OEMCryptoProv30Test, OEMCertForbiddenPaddingScheme) {
   vector<uint8_t> data(500);
   GetRandBytes(&data[0], data.size());
   size_t signature_length = 0;
-  vector<uint8_t> signature(1);
+  // We need a size one vector to pass as a pointer.
+  vector<uint8_t> signature(1, 0);
+  vector<uint8_t> zero(1, 0);
 
   sts = OEMCrypto_GenerateRSASignature(s.session_id(), &data[0], data.size(),
                                        &signature[0], &signature_length,
                                        kSign_PKCS1_Block1);
   if (OEMCrypto_ERROR_SHORT_BUFFER == sts) {
+    // The OEMCrypto could complain about buffer length first, so let's
+    // resize and check if it's writing to the signature again.
     signature.resize(signature_length, 0);
+    zero.resize(signature_length, 0);
     sts = OEMCrypto_GenerateRSASignature(s.session_id(), &data[0], data.size(),
                                          &signature[0], &signature_length,
                                          kSign_PKCS1_Block1);
   }
   EXPECT_NE(OEMCrypto_SUCCESS, sts)
       << "OEM Cert Signed with forbidden kSign_PKCS1_Block1.";
-  vector<uint8_t> zero(signature_length, 0);
   ASSERT_EQ(zero, signature);  // signature should not be computed.
 }