diff --git a/ext/openssl/ossl_pkcs7.c b/ext/openssl/ossl_pkcs7.c
index c53e512e8..cf49598c8 100644
--- a/ext/openssl/ossl_pkcs7.c
+++ b/ext/openssl/ossl_pkcs7.c
@@ -510,6 +510,8 @@ ossl_pkcs7_get_detached(VALUE self)
 {
     PKCS7 *p7;
     GetPKCS7(self, p7);
+    if (!PKCS7_type_is_signed(p7))
+        return Qfalse;
     return PKCS7_get_detached(p7) ? Qtrue : Qfalse;
 }
 
diff --git a/test/openssl/test_pkcs7.rb b/test/openssl/test_pkcs7.rb
index 5245ec1a6..cb6cce0ff 100644
--- a/test/openssl/test_pkcs7.rb
+++ b/test/openssl/test_pkcs7.rb
@@ -265,6 +265,7 @@ def test_data
 
     p7 = OpenSSL::PKCS7.new(asn1)
     assert_equal(:data, p7.type)
+    assert_equal(false, p7.detached)
     assert_equal(false, p7.detached?)
     # Not applicable
     assert_nil(p7.certificates)