diff --git a/bramble-core/src/main/java/org/briarproject/bramble/mailbox/sessions/FeedableSyncInputStream.java b/bramble-core/src/main/java/org/briarproject/bramble/mailbox/sessions/FeedableSyncInputStream.java
index e5310130fadc7232abf74a62cfbe66b7eb7779b6..40ba8f48fdea7bef2d17fe4b22bc810620bdc0e6 100644
--- a/bramble-core/src/main/java/org/briarproject/bramble/mailbox/sessions/FeedableSyncInputStream.java
+++ b/bramble-core/src/main/java/org/briarproject/bramble/mailbox/sessions/FeedableSyncInputStream.java
@@ -24,7 +24,7 @@ public class FeedableSyncInputStream extends InputStream {
 			}
 		}
 
-		return activeBuffer[activeBufferPointer++];
+		return activeBuffer[activeBufferPointer++] & 0xff;
 	}
 
 	private boolean hasBytes() {