diff --git a/src/main/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinition.java b/src/main/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinition.java
index a1d018b..c693e9c 100644
--- a/src/main/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinition.java
+++ b/src/main/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinition.java
@@ -36,6 +36,7 @@
 import jenkins.model.Jenkins;
 import net.sf.json.JSONObject;
 import org.apache.commons.fileupload.FileItem;
+import org.apache.commons.fileupload.FileUploadBase;
 import org.kohsuke.stapler.DataBoundSetter;
 import org.kohsuke.stapler.StaplerRequest;
 
@@ -78,9 +79,18 @@ protected AbstractFileParameterDefinition(String name) {
 
     @Override public ParameterValue createValue(StaplerRequest req) {
         try {
-            FileItem src = req.getFileItem(getName());
+            FileItem src;
+            try {
+                src = req.getFileItem(getName());
+            } catch (ServletException x) {
+                if (x.getCause() instanceof FileUploadBase.InvalidContentTypeException) {
+                    src = null;
+                } else {
+                    throw x;
+                }
+            }
             if (src == null) {
-                throw new RuntimeException("No file was uploaded");
+                return null;
             }
             AbstractFileParameterValue p;
             try (InputStream in = src.getInputStream()) {
diff --git a/src/test/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinitionTest.java b/src/test/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinitionTest.java
index b94092e..cd48523 100644
--- a/src/test/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinitionTest.java
+++ b/src/test/java/io/jenkins/plugins/file_parameters/AbstractFileParameterDefinitionTest.java
@@ -48,6 +48,7 @@
 import org.junit.Rule;
 import org.junit.rules.TemporaryFolder;
 import org.jvnet.hudson.test.BuildWatcher;
+import org.jvnet.hudson.test.Issue;
 import org.jvnet.hudson.test.JenkinsRule;
 import org.jvnet.hudson.test.MockAuthorizationStrategy;
 
@@ -95,4 +96,21 @@ public class AbstractFileParameterDefinitionTest {
         r.assertLogContains("received myfile.txt: dXBsb2FkZWQgY29udGVudCBoZXJl", b);
     }
 
+    @Issue("https://github.com/jenkinsci/file-parameters-plugin/issues/26")
+    @Test public void restMissingValue() throws Exception {
+        r.jenkins.setSecurityRealm(r.createDummySecurityRealm());
+        r.jenkins.setAuthorizationStrategy(new MockAuthorizationStrategy().grant(Jenkins.ADMINISTER).everywhere().to("admin"));
+        WorkflowJob p = r.createProject(WorkflowJob.class, "myjob");
+        p.addProperty(new ParametersDefinitionProperty(new Base64FileParameterDefinition("FILE")));
+        p.setDefinition(new CpsFlowDefinition("echo(/received $env.FILE_FILENAME: $env.FILE/)", true));
+        // Like: curl -u $auth $jenkins/job/myjob/buildWithParameters
+        WebRequest req = new WebRequest(new URL(r.getURL() + "job/myjob/buildWithParameters"), HttpMethod.POST);
+        User.getById("admin", true); // TODO workaround for https://github.com/jenkinsci/jenkins-test-harness/pull/273
+        r.createWebClient().withBasicApiToken("admin").getPage(req);
+        r.waitUntilNoActivity();
+        WorkflowRun b = p.getBuildByNumber(1);
+        assertNotNull(b);
+        r.assertLogContains("received null: null", b);
+    }
+
 }