diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 5039ca1c..3923b6cb 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -29,7 +29,7 @@ jobs:
     # reference the image by its SHA rather than its tag because they sometimes
     # overwrite a tag with a different image (which has a different SHA).  This
     # SHA corresponds to tag "asciidoctor-spec.20240727".
-    container: khronosgroup/docker-images@sha256:sha256:089687083ceb36483a3917389e4278718ab19c594099634f5dd80e22540c960f
+    container: khronosgroup/docker-images@sha256:089687083ceb36483a3917389e4278718ab19c594099634f5dd80e22540c960f
 
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it