diff --git a/maven-core/src/main/java/org/apache/maven/DefaultMaven.java b/maven-core/src/main/java/org/apache/maven/DefaultMaven.java
index 7bed0639a1..b1f239acec 100644
--- a/maven-core/src/main/java/org/apache/maven/DefaultMaven.java
+++ b/maven-core/src/main/java/org/apache/maven/DefaultMaven.java
@@ -264,6 +264,8 @@ public class DefaultMaven
             return processResult( result, e );
         }
 
+        repoSession.setReadOnly();
+
         ClassLoader originalClassLoader = Thread.currentThread().getContextClassLoader();
         try
         {