diff --git a/act/runner/testdata/actions/action1/Dockerfile b/act/runner/testdata/actions/action1/Dockerfile
index 311a4a0b..a5bf22a4 100644
--- a/act/runner/testdata/actions/action1/Dockerfile
+++ b/act/runner/testdata/actions/action1/Dockerfile
@@ -1 +1 @@
-FROM ubuntu:18.04
\ No newline at end of file
+FROM ubuntu:26.04
\ No newline at end of file