diff --git a/Dockerfile b/Dockerfile
index 079bd9b..822c1ce 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
 # Base image pinned by its multi-arch index digest, so a re-pushed tag cannot
 # change what is built. Refresh the digest and the tag together.
-FROM python:3.11.15-slim-bookworm@sha256:d29f48a31a8b408ed19272ca1e7b10ebae13b240a27e862d3d4217c528e2e0c3 AS builder
+FROM python:3.11.16-slim-bookworm@sha256:a36c24f9cbdf4fd0f52d67f0823eeac19c2028c637cecc392d97f980d4fec56b AS builder
 
 ENV PIP_DISABLE_PIP_VERSION_CHECK=1 \
     PIP_NO_CACHE_DIR=1
@@ -14,7 +14,7 @@ COPY pyproject.toml README.md LICENSE NOTICE ./
 COPY src ./src
 RUN python -m pip wheel --no-deps --no-build-isolation --wheel-dir /wheels .
 
-FROM python:3.11.15-slim-bookworm@sha256:d29f48a31a8b408ed19272ca1e7b10ebae13b240a27e862d3d4217c528e2e0c3 AS runtime
+FROM python:3.11.16-slim-bookworm@sha256:a36c24f9cbdf4fd0f52d67f0823eeac19c2028c637cecc392d97f980d4fec56b AS runtime
 
 ENV PIP_DISABLE_PIP_VERSION_CHECK=1 \
     PIP_NO_CACHE_DIR=1 \
diff --git a/tests/unit/test_container_release.py b/tests/unit/test_container_release.py
index 430a6a0..257fac8 100644
--- a/tests/unit/test_container_release.py
+++ b/tests/unit/test_container_release.py
@@ -12,7 +12,7 @@
 def test_runtime_image_is_multistage_non_root_and_offline_installed() -> None:
     dockerfile = Path("Dockerfile").read_text(encoding="utf-8")
     # Both stages pin the base image by digest, not by tag alone.
-    assert dockerfile.count("FROM python:3.11.15-slim-bookworm@sha256:") == 2
+    assert dockerfile.count("FROM python:3.11.16-slim-bookworm@sha256:") == 2
     assert "AS builder" in dockerfile
     assert "pip install --require-hashes -r requirements/build.txt" in dockerfile
     assert "pip wheel --no-deps --no-build-isolation --wheel-dir /wheels ." in dockerfile