Cloudanix VulnDB

CVE-2026-55455

Critical · 9.1

CVSS

9.1

EPSS

0.4%

Published

Jun 24, 2026

CISA due date

—

The record

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.

Affected packages

Ecosystem Package Introduced Fixed

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