diff --git a/taskcluster/docker/fetch/Dockerfile b/taskcluster/docker/fetch/Dockerfile
index 27f8d91..2acb708 100644
--- a/taskcluster/docker/fetch/Dockerfile
+++ b/taskcluster/docker/fetch/Dockerfile
@@ -1,4 +1,4 @@
-FROM debian:11
+FROM debian:13
 
 ### Add worker user and setup its workspace.
 RUN mkdir -p /builds && \
diff --git a/taskcluster/docker/python/Dockerfile b/taskcluster/docker/python/Dockerfile
index 8fb5096..7555609 100644
--- a/taskcluster/docker/python/Dockerfile
+++ b/taskcluster/docker/python/Dockerfile
@@ -2,7 +2,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-FROM debian:12-slim
+FROM debian:13-slim
 LABEL maintainer="Mozilla Release Engineering <release+mozilla-taskgraph@mozilla.com>"
 
 VOLUME /builds/worker/checkouts