diff --git a/internal_headers/certifier/error.h b/internal_headers/certifier/error.h
index c4f1ff7..588abf5 100644
--- a/internal_headers/certifier/error.h
+++ b/internal_headers/certifier/error.h
@@ -38,6 +38,9 @@ typedef struct
     char * library_error_msg;
 } CertifierError;
 
+/* NOTE: After assign_last_error(certifier, &tmp_err), do not call error_clear(&tmp_err) for the message pointers (they no longer belong to tmp_err). 
+ * It’s safe to reuse tmp_err for codes, but not to free its message fields because they were moved.
+ */
 void error_clear(CertifierError * error);
 
 enum
diff --git a/src/certifier.c b/src/certifier.c
index 93b0f3f..d60c1e5 100644
--- a/src/certifier.c
+++ b/src/certifier.c
@@ -845,7 +845,15 @@ void certifier_print_certificate_validity(Certifier * certifier)
 static inline void assign_last_error(Certifier * certifier, CertifierError * error)
 {
     error_clear(&certifier->last_error);
-    certifier->last_error = *error;
+    certifier->last_error.application_error_code = error->application_error_code;
+    certifier->last_error.library_error_code     = error->library_error_code;
+    certifier->last_error.application_error_msg  = error->application_error_msg;
+    certifier->last_error.library_error_msg      = error->library_error_msg;
+    // Prevent double-free by nulling source pointers
+    error->application_error_msg = NULL;
+    error->library_error_msg     = NULL;
+    error->application_error_code = 0;
+    error->library_error_code     = 0;
 }
 
 /**