diff --git a/pn_oim.c b/pn_oim.c
index 6faaabe..496e3c0 100644
--- a/pn_oim.c
+++ b/pn_oim.c
@@ -576,7 +576,8 @@ process_body_receive (OimRequest *oim_request,
         gchar *end;
         cur += 2;
         end = strstr (cur, "\r\n\r\n");
-        *end = '\0';
+        if (end)
+            *end = '\0';
         message = (gchar *) purple_base64_decode (cur, NULL);
     }