diff --git a/Dockerfile b/Dockerfile
index 8fecc77..4c0e1d3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,6 +18,6 @@ RUN set -ex; \
     npx grunt prod; \
     rm /tmp/cyberchef/build/prod/BundleAnalyzerReport.html /tmp/cyberchef/build/prod/CyberChef_$CYBERCHEF_VERSION.zip;
 
-FROM nginxinc/nginx-unprivileged:1.18.0
+FROM nginxinc/nginx-unprivileged:1.18.0@sha256:867ba87397912e0b1d8c1082b36bd372adc810ef28f1a8be4261dc91dbac03d4
 COPY --from=build /tmp/cyberchef/build/prod /usr/share/nginx/html
 EXPOSE 8080