diff --git a/src/java/org/rapidcontext/util/FileUtil.java b/src/java/org/rapidcontext/util/FileUtil.java
index 126ef4f1..f2430d59 100644
--- a/src/java/org/rapidcontext/util/FileUtil.java
+++ b/src/java/org/rapidcontext/util/FileUtil.java
@@ -271,7 +271,7 @@ public static void setTempDir(File dir) {
     public static File tempFile(String name) throws IOException {
         String prefix = StringUtils.substringBeforeLast(name, ".");
         String suffix = StringUtils.substringAfterLast(name, ".");
-        if (prefix == null || prefix.isBlank()) {
+        if (prefix == null || prefix.isBlank() || prefix.length() < 3) {
             prefix = "file";
         }
         if (suffix != null && !suffix.isBlank()) {