diff --git a/infra/images/docs.Dockerfile b/infra/images/docs.Dockerfile
index a07e7f1..05ec256 100644
--- a/infra/images/docs.Dockerfile
+++ b/infra/images/docs.Dockerfile
@@ -19,12 +19,15 @@ RUN uv run --with griffe python docs/scripts/extract_docs.py
 
 
 # Stage 2: Build Docusaurus static site
-FROM node:22-slim AS build
+FROM node:26-slim AS build
 
 # No `corepack prepare <version>`: corepack runs the pnpm that
 # docs/package.json's packageManager names, so Renovate's bump of that
 # field is the whole upgrade (a second pin here went stale at pnpm 12).
-RUN corepack enable
+# Node 25+ no longer bundles corepack, so install a pinned one from npm.
+# renovate: datasource=npm depName=corepack
+ARG COREPACK_VERSION=0.36.0
+RUN npm install -g corepack@${COREPACK_VERSION} && corepack enable
 
 WORKDIR /docs
 
diff --git a/infra/images/notebooks.Dockerfile b/infra/images/notebooks.Dockerfile
index 73be3f8..979431a 100644
--- a/infra/images/notebooks.Dockerfile
+++ b/infra/images/notebooks.Dockerfile
@@ -22,13 +22,17 @@ ARG MARIMO_VERSION=0.25.2
 
 # ---- stage 1: frontend ------------------------------------------------------
 
-FROM node:22-bookworm-slim AS fe
+FROM node:26-bookworm-slim AS fe
 ARG MARIMO_VERSION
 WORKDIR /src
 
+# Node 25+ no longer bundles corepack, so install a pinned one from npm.
+# renovate: datasource=npm depName=corepack
+ARG COREPACK_VERSION=0.36.0
 RUN apt-get update \
     && apt-get install -y --no-install-recommends git ca-certificates python3 jq \
     && rm -rf /var/lib/apt/lists/* \
+    && npm install -g corepack@${COREPACK_VERSION} \
     && corepack enable
 # No `corepack prepare pnpm@latest`: the corepack shim resolves the exact
 # pnpm version from marimo's package.json `packageManager` field at first