diff --git a/core/src/main/java/com/threerings/io/ObjectInputStream.java b/core/src/main/java/com/threerings/io/ObjectInputStream.java
index 0ca770352..6b0a5326c 100644
--- a/core/src/main/java/com/threerings/io/ObjectInputStream.java
+++ b/core/src/main/java/com/threerings/io/ObjectInputStream.java
@@ -258,7 +258,8 @@ public class ObjectInputStream extends DataInputStream
                 checkName = checkName.substring(1, checkName.length() - 1);
             }
 
-            boolean allowed = false;
+            // primitive array descriptors (I, Z, B, S, C, J, F, D) are always safe
+            boolean allowed = (checkName.length() == 1);
             for (String prefix : _allowedPrefixes) {
                 if (checkName.startsWith(prefix)) {
                     allowed = true;