diff --git a/briar-core/src/main/java/org/briarproject/briar/avatar/AvatarManagerImpl.java b/briar-core/src/main/java/org/briarproject/briar/avatar/AvatarManagerImpl.java
index 5e8818d14..5258458f4 100644
--- a/briar-core/src/main/java/org/briarproject/briar/avatar/AvatarManagerImpl.java
+++ b/briar-core/src/main/java/org/briarproject/briar/avatar/AvatarManagerImpl.java
@@ -135,6 +135,11 @@ class AvatarManagerImpl implements AvatarManager, OpenDatabaseHook, ContactHook,
 	@Override
 	public boolean incomingMessage(Transaction txn, Message m, Metadata meta)
 			throws DbException, InvalidMessageException {
+		Group ourGroup = getOurGroup(txn);
+		if (m.getGroupId().equals(ourGroup.getId())) {
+			throw new InvalidMessageException(
+					"Received incoming message in my avatar group");
+		}
 		try {
 			// Find the latest update, if any
 			BdfDictionary d = metadataParser.parse(meta);
diff --git a/briar-core/src/test/java/org/briarproject/briar/avatar/AvatarManagerImplTest.java b/briar-core/src/test/java/org/briarproject/briar/avatar/AvatarManagerImplTest.java
index b83c063a1..9a0436634 100644
--- a/briar-core/src/test/java/org/briarproject/briar/avatar/AvatarManagerImplTest.java
+++ b/briar-core/src/test/java/org/briarproject/briar/avatar/AvatarManagerImplTest.java
@@ -180,6 +180,7 @@ public class AvatarManagerImplTest extends BrambleMockTestCase {
 				new BdfEntry(MSG_KEY_CONTENT_TYPE, contentType)
 		);
 
+		expectGetOurGroup(txn);
 		context.checking(new Expectations() {{
 			oneOf(metadataParser).parse(meta);
 			will(returnValue(d));
@@ -211,6 +212,7 @@ public class AvatarManagerImplTest extends BrambleMockTestCase {
 				new BdfEntry(MSG_KEY_CONTENT_TYPE, contentType)
 		);
 
+		expectGetOurGroup(txn);
 		context.checking(new Expectations() {{
 			oneOf(metadataParser).parse(meta);
 			will(returnValue(d));
@@ -241,6 +243,7 @@ public class AvatarManagerImplTest extends BrambleMockTestCase {
 				new BdfEntry(MSG_KEY_CONTENT_TYPE, contentType)
 		);
 
+		expectGetOurGroup(txn);
 		context.checking(new Expectations() {{
 			oneOf(metadataParser).parse(meta);
 			will(returnValue(d));
@@ -256,6 +259,14 @@ public class AvatarManagerImplTest extends BrambleMockTestCase {
 		assertEquals(0, txn.getActions().size());
 	}
 
+	@Test(expected = InvalidMessageException.class)
+	public void testIncomingMessageInOwnGroup()
+			throws DbException, InvalidMessageException, FormatException {
+		Transaction txn = new Transaction(null, false);
+		expectGetOurGroup(txn);
+		avatarManager.incomingMessage(txn, ourMsg, meta);
+	}
+
 	@Test
 	public void testAddAvatar() throws Exception {
 		byte[] avatarBytes = getRandomBytes(42);