What is the CVSS score of CVE-2026-55454?

CVE-2026-55454 has a CVSS 3.1 base score of 9.9 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of Appsmith are affected by CVE-2026-55454?

Appsmith versions prior to 2.1 contain a critical vulnerability allowing authenticated low-privileged users to seize control of the bundled reverse proxy, potentially compromising the entire…. A patch is available.

How to fix or mitigate CVE-2026-55454?

24 hours: Inventory all Appsmith instances and confirm version levels; enable logging for reverse-proxy configuration changes and port 2019 access; restrict network egress from containers to block internal SSRF. 7 days: Analyze access logs for abnormal POST requests to 127.0.0.1:2019; audit user roles and disable unnecessary low-privileged accounts; monitor vendor advisories for Appsmith 2.1+ release timeline. 30 days: Deploy upgrade to Appsmith 2.1 or later upon release; validate remediation via network inspection; deploy WAF rules blocking SSRF payloads targeting 127.0.0.1:2019.

Appsmith CVE-2026-55454

EUVD-2026-39118 CRITICAL

Exposed Dangerous Method or Function (CWE-749)

2026-06-24 GitHub_M

SSRF Docker Appsmith

9.9

CVSS 3.1 · Vendor: GitHub_M

Severity by source

Vendor (GitHub_M) PRIMARY

9.9 CRITICAL

AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

vuln.today AI

9.9 CRITICAL

Low-priv authenticated user (PR:L) drives an SSRF over the network (AV:N/AC:L); reverse-proxy takeover is a scope change (S:C) with full C/I/A compromise of fronted traffic.

3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Patch available

Jun 24, 2026 - 23:03 EUVD

Analysis Generated

Jun 24, 2026 - 22:25 vuln.today

CVE Published

Jun 24, 2026 - 21:38 cve.org

CRITICAL 9.9

DescriptionCVE.org

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.

Articles & Coverage 1

News Critical SSRF to Reverse-Proxy Takeover in Appsmith/Docker - CVE-2026-55454 Jun 24, 2026

AnalysisAI

Reverse-proxy takeover in Appsmith versions prior to 2.1 lets an authenticated low-privileged user abuse server-side request forgery to reach the bundled Caddy admin API, which ships with no authentication and listens on 0.0.0.0:2019 inside the container. By forcing the Appsmith server to issue a POST /load to that internal endpoint, the attacker rewrites the live Caddy configuration and seizes control of the reverse proxy that fronts the application. No public exploit identified at time of analysis and the issue is not in CISA KEV, but the vendor-confirmed CWE-749 exposure carries a 9.9 CVSS rating.

Technical ContextAI

Appsmith is a self-hosted, low-code platform for building internal admin panels, dashboards, and CRUD tools, typically deployed as a single Docker container via docker-compose. That container bundles the Caddy web server acting as a reverse proxy in front of the Appsmith backend. Caddy exposes an administrative REST API (default port 2019) that can fully reconfigure the running server at runtime; by design this API has no authentication and is meant to be bound to loopback only. The root cause maps to CWE-749 (Exposed Dangerous Method or Function): in the vulnerable image Caddy's admin listener is bound to 0.0.0.0:2019 rather than 127.0.0.1, making the dangerous configuration-replacement method reachable to any process inside the container - and, by extension, to any SSRF primitive that can coerce outbound requests from the Appsmith server. The affected component is identified by CPE cpe:2.3:a:appsmithorg:appsmith:*:*:*:*:*:*:*:* for all builds before 2.1.

RemediationAI

Upgrade to Appsmith 2.1 or later, which is the vendor-released patch that corrects the Caddy admin-API binding (Vendor-released patch: 2.1; see GHSA-8jvv-gwqg-6vjc at https://github.com/appsmithorg/appsmith/security/advisories/GHSA-8jvv-gwqg-6vjc). If you cannot upgrade immediately, rebind the Caddy admin listener to loopback by setting the admin endpoint to 127.0.0.1:2019 (or 'admin off' if runtime reconfiguration is not needed) in the container's Caddyfile/JSON config - this directly removes the 0.0.0.0 exposure but requires rebuilding or overriding the bundled image and means you lose remote admin-API management. As a complementary control, add container-level firewalling/network policy to block traffic to port 2019 from any source other than localhost, and tighten Appsmith data-source/API permissions for low-privileged users to shrink the SSRF surface; be aware that restricting outbound request features may break legitimate connectors your builders rely on.