diff --git a/frontend/Dockerfile b/frontend/Dockerfile
index 33e150c..edc8f12 100644
--- a/frontend/Dockerfile
+++ b/frontend/Dockerfile
@@ -14,7 +14,7 @@ ENV SITE_URL=${SITE_URL}
 RUN npm run build
 
 # ---- Runtime ----------------------------------------------------------------
-FROM nginxinc/nginx-unprivileged:1.29-alpine
+FROM nginxinc/nginx-unprivileged:1.31-alpine
 
 # Where /api/ is proxied to; substituted into the template at start-up.
 ENV API_UPSTREAM=api:8080