diff --git a/Dockerfile b/Dockerfile
index 7befb464..d556008b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -20,8 +20,8 @@ FROM ${NODE_IMAGE} AS frontend-builder
 
 WORKDIR /app/frontend
 
-# Install pnpm
-RUN corepack enable && corepack prepare pnpm@latest --activate
+# Install pnpm (pinned to v9 to match CI and keep builds reproducible)
+RUN corepack enable && corepack prepare pnpm@9 --activate
 
 # Install dependencies first (better caching)
 COPY frontend/package.json frontend/pnpm-lock.yaml ./