Appsmith: community verdicts

Appsmith is a platform to build admin panels, internal tools, and dashboards. Prior to 2.1, the bundled Caddy reverse-proxy's admin API — which has no authentication by default — is bound on 0.0.0.0:2019 inside the container. While this listener is not directly published to the host by docker-compose.yml, it is reachable from the Appsmith server process itself or a SSRF vulnerability. An authenticated low-privileged user can therefore drive the SSRF to issue POST /load (or any other admin-API call) against http://0.0.0.0:2019/, fully replacing the live Caddy configuration and taking over the reverse proxy. This vulnerability is fixed in 2.1.

Appsmith is a platform to build admin panels, internal tools, and dashboards. Prior to 2.1, Appsmith's bundled supervisord exposes an XML-RPC interface on port 9001, reachable from outside the container via a Caddy reverse-proxy route at /supervisor/* on the public ingress. Combined with the APPSMITH_SUPERVISOR_PASSWORD exposed via GET /api/v1/admin/env, any authenticated administrator can send arbitrary XML-RPC calls to supervisord and execute OS commands inside the Docker container via twiddler.addProgramToGroup. This vulnerability is fixed in 2.1.

Appsmith is a platform to build admin panels, internal tools, and dashboards. Prior to 2.1, the outbound HTTP host filter applied by WebClientUtils (used by the REST API and GraphQL datasource plugins) validates hosts against an exact-match string denylist. The comprehensive address-class check (loopback, any-local, link-local, fc00::/7) exists only on a separate code path used by SMTP, not by the HTTP plugin path. As a result, an authenticated user can craft outbound requests that reach loopback-bound services inside the container. This vulnerability is fixed in 2.1.