diff --git a/serde/src/de/impls.rs b/serde/src/de/impls.rs
index 2946dcfe..5f5307fd 100644
--- a/serde/src/de/impls.rs
+++ b/serde/src/de/impls.rs
@@ -305,9 +305,8 @@ impl Deserialize for CString {
     fn deserialize<D>(deserializer: D) -> Result<CString, D::Error>
         where D: Deserializer
     {
-        let v: Vec<u8> = try!(ByteBuf::deserialize(deserializer)).into();
-        CString::new(v)
-            .map_err(|e| Error::custom(format!("unexpected NULL at byte {}", e.nul_position())))
+        let bytes = try!(ByteBuf::deserialize(deserializer));
+        CString::new(bytes).map_err(Error::custom)
     }
 }
 
diff --git a/test_suite/tests/test_de.rs b/test_suite/tests/test_de.rs
index 8e79f1f1..fa5943c2 100644
--- a/test_suite/tests/test_de.rs
+++ b/test_suite/tests/test_de.rs
@@ -1005,12 +1005,12 @@ declare_error_tests! {
         &[
             Token::Bytes(b"a\0c"),
         ],
-        Error::Message("unexpected NULL at byte 1".into()),
+        Error::Message("nul byte found in provided data at position: 1".into()),
     }
     test_cstring_internal_null_end<CString> {
         &[
             Token::Bytes(b"ac\0"),
         ],
-        Error::Message("unexpected NULL at byte 2".into()),
+        Error::Message("nul byte found in provided data at position: 2".into()),
     }
 }