CVE-2026-55454: Appsmith: Caddy admin API exposed without authentication

Severity: critical (CVSS 9.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-24 · updated 2026-10-25
Weakness: CWE-749

Description

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.

Affected products

appsmithorg appsmith: before 2.1 — fixed in 2.1

How to fix

Upgrade to a fixed version: appsmithorg appsmith 2.1. Check the vendor advisory for mitigations.

References

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