diff --git a/Dockerfile b/Dockerfile
index 08d810a..42c1159 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
-FROM python:3.11-slim AS base
+FROM python:3.11.16-slim AS base
 
 # Install uv (fast Python package manager) from official slim image.
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /usr/local/bin/
+COPY --from=ghcr.io/astral-sh/uv:0.10.9 /uv /uvx /usr/local/bin/
 
 # System libs required by WeasyPrint at runtime.
 RUN apt-get update && apt-get install -y --no-install-recommends \
@@ -13,6 +13,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     shared-mime-info \
     && rm -rf /var/lib/apt/lists/*
 
+# Non-root user the app runs as at runtime.
+RUN useradd -u 10001 app
+
 WORKDIR /app
 
 # Copy lockfile + project metadata first to maximize Docker layer cache.
@@ -27,7 +30,10 @@ RUN uv sync --frozen --no-dev --extra server
 COPY src/ ./src/
 
 # Uploads directory (mounted as a volume in production).
-RUN mkdir -p /app/uploads/images /app/uploads/pdfs /app/uploads/logos /app/uploads/reports
+RUN mkdir -p /app/uploads/images /app/uploads/pdfs /app/uploads/logos /app/uploads/reports \
+    && chown -R app:app /app
+
+USER app
 
 EXPOSE 8000
 
diff --git a/Dockerfile.frontend b/Dockerfile.frontend
index c2e4a78..027eb88 100644
--- a/Dockerfile.frontend
+++ b/Dockerfile.frontend
@@ -1,13 +1,25 @@
-FROM python:3.11-slim AS base
+# TailwindCSS built in its own stage, from the official Node image, instead
+# of `curl | bash` against nodesource inside the final image (point 2, C2).
+FROM node:20.20.2-bookworm-slim AS tailwind-build
+
+WORKDIR /app/flask_app
+COPY src/frontend/flask_app/ ./
+
+# Versione esatta, non `tailwindcss@3`. Con il vincolo aperto ogni ricostruzione
+# dell'immagine poteva prendere una minor diversa e produrre un CSS diverso senza
+# che nessuno l'avesse validato: per un sistema che produce evidenze per audit
+# ISO 9001 / IATF 16949 è lo stesso problema che il punto 12 risolve per le
+# librerie del browser. Aggiornarla è una decisione, non un effetto collaterale.
+RUN npm install tailwindcss@3.4.19 && \
+    npx tailwindcss -i static/css/input.css -o static/css/tailwind.css --minify
+
+FROM python:3.11.16-slim AS base
 
 # uv from the official slim image (fast Python package manager).
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /usr/local/bin/
+COPY --from=ghcr.io/astral-sh/uv:0.10.9 /uv /uvx /usr/local/bin/
 
-# Node.js 20 is needed at build time to compile TailwindCSS.
-RUN apt-get update && apt-get install -y --no-install-recommends curl ca-certificates \
-    && curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
-    && apt-get install -y --no-install-recommends nodejs \
-    && rm -rf /var/lib/apt/lists/*
+# Non-root user the app runs as at runtime.
+RUN useradd -u 10001 app
 
 WORKDIR /app
 
@@ -16,22 +28,17 @@ COPY pyproject.toml uv.lock ./
 COPY .python-version ./
 RUN uv sync --frozen --no-dev --extra client
 
-# Copy the Flask app sources.
+# Copy the Flask app sources, then overlay the TailwindCSS build produced in
+# the node stage above — the final image never installs Node.
 COPY src/frontend/flask_app/ ./flask_app/
-
-# Build TailwindCSS (one-shot; no watcher in production image).
-#
-# Versione esatta, non `tailwindcss@3`. Con il vincolo aperto ogni ricostruzione
-# dell'immagine poteva prendere una minor diversa e produrre un CSS diverso senza
-# che nessuno l'avesse validato: per un sistema che produce evidenze per audit
-# ISO 9001 / IATF 16949 è lo stesso problema che il punto 12 risolve per le
-# librerie del browser. Aggiornarla è una decisione, non un effetto collaterale.
-WORKDIR /app/flask_app
-RUN npm install tailwindcss@3.4.19 && \
-    npx tailwindcss -i static/css/input.css -o static/css/tailwind.css --minify
+COPY --from=tailwind-build /app/flask_app/static/css/tailwind.css ./flask_app/static/css/tailwind.css
 
 # Compile Flask-Babel translation catalogs.
-RUN uv run --project /app pybabel compile -d translations
+WORKDIR /app/flask_app
+RUN uv run --project /app pybabel compile -d translations && \
+    chown -R app:app /app
+
+USER app
 
 EXPOSE 5000
 
diff --git a/Dockerfile.vision b/Dockerfile.vision
index 7e29cb1..7cfffed 100644
--- a/Dockerfile.vision
+++ b/Dockerfile.vision
@@ -1,4 +1,4 @@
-FROM python:3.13-slim
+FROM python:3.13.15-slim
 
 # opencv-python (pulled in transitively by vs-core/vs-task/vs-measure/vs-pm2d)
 # needs libGL and glib at runtime even though it is never imported by name here.
@@ -6,7 +6,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
         libgl1 libglib2.0-0 \
     && rm -rf /var/lib/apt/lists/*
 
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /usr/local/bin/uv
+COPY --from=ghcr.io/astral-sh/uv:0.10.9 /uv /usr/local/bin/uv
+
+# Non-root user the app runs as at runtime. Same UID as the server's Dockerfile
+# so both containers agree on ownership of the shared uploads volume (point 13).
+RUN useradd -u 10001 app
 
 WORKDIR /app
 COPY pyproject.toml uv.lock ./
@@ -34,6 +38,9 @@ RUN test -n "$VISION_ENGINE_VERSION" || { \
     }
 ENV VISION_ENGINE_VERSION=${VISION_ENGINE_VERSION}
 
+RUN chown -R app:app /app
+USER app
+
 EXPOSE 8100
 
 # Two workers, not four: each holds the vision stack in memory.