TI-2026-40019 Aliases CVE-2026-55455

Appsmith: SSRF in REST API / GraphQL datasource plugins via insufficient host denylist

MEDIUM 57CWE-918Published 2026-06-24 · Updated 2026-06-25

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: —
Confidentiality · integrity · availability: Low · Low · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00388 33rd percentileScored 2026-11-07

Fix Fixed appsmith (appsmithorg): 2.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
appsmithorg	appsmith	before 2.1	2.1	Patch available	CNA

appsmith Vendorappsmithorg Affected before 2.1 Fixed in 2.1 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:appsmith:appsmith::::::::	before 2.1	Vulnerable	appsmithorg

cpe:2.3:a:appsmith:appsmith:*:*:*:*:*:*:*:* Versions before 2.1 Vulnerable ·appsmithorg

Remediation

Fix · CNA appsmith (appsmithorg) Fixed in 2.1

Timeline

2026-10-02 Threatist record created from CVE-2026-55455

References

Advisory 1

https://github.com/appsmithorg/appsmith/security/advisories/GHSA-m23h-pvf3-2m7p

TI-2026-40018 Appsmith: Caddy admin API exposed without authentication CVSS 3.1CRITICAL 9.9
TI-2026-18312 Account Takeover Vulnerability in Appsmith CVSS 3.1CRITICAL 9.7
TI-2026-36948 Appsmith: RCE via Supervisord XML-RPC Admin Interface Exposed via /supervisor Caddy Route CVSS 4.0HIGH 8.9
TI-2026-23691 Critical Stored XSS & Privilege Escalation in Appsmith CVSS 3.1CRITICAL 9.1
TI-2024-34357 AppSmith Community 1.8.3 before 1.46 allows SSRF via New DataSource for application/json… CVSS 3.1HIGH 8.5
TI-2022-03744 Server-Side Request Forgery (SSRF) in appsmithorg/appsmith CVSS 3.1MEDIUM 6.5

See all 17 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences