diff --git a/src/lib.rs b/src/lib.rs
index 17dc0ccd..f33d7cca 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1341,9 +1341,11 @@ pub fn z85_decode(data: &str) -> result::Result<Vec<u8>, DecodeError> {
     let mut dest = vec![0u8; len];
 
     let c_str = ffi::CString::new(data)?;
+    let c_str_ptr = c_str.into_raw();
 
     unsafe {
-        zmq_sys::zmq_z85_decode(dest.as_mut_ptr(), c_str.into_raw());
+        zmq_sys::zmq_z85_decode(dest.as_mut_ptr(), c_str_ptr);
+        drop(ffi::CString::from_raw(c_str_ptr));
     }
 
     Ok(dest)