CVE-2026-55455
Last modified
CVE-2026-55455 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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. EPSS estimates a 0.22% chance of exploitation in the next 30 days.
Description
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Appsmith | Appsmith | < 2.1 |
References
- https://github.com/appsmithorg/appsmith/security/advisories/GHSA-m23h-pvf3-2m7pThird Party Advisory
- https://github.com/appsmithorg/appsmith/security/advisories/GHSA-m23h-pvf3-2m7pThird Party Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-55455?
How severe is CVE-2026-55455?
How do I fix CVE-2026-55455?
How Strix Helps
- One Click Account Takeover in GranolaHow a notification link broke out of Electron and led to a one-click account takeover.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-55447Langflow is a tool for building and deploying AI-powered age…9.6
- CVE-2026-55448mise manages dev tools like node, python, cmake, and terrafo…6.3
- CVE-2026-5545libcurl might in some circumstances reuse the wrong connecti…6.5
- CVE-2026-55450Langflow is a tool for building and deploying AI-powered age…9.3
- CVE-2026-55452Snipe-IT is an IT asset/license management system. Prior to …7.3
- CVE-2026-55454Appsmith is a platform to build admin panels, internal tools…9.9
- CVE-2026-5546A flaw has been found in Campcodes Complete Online Learning …6.3
- CVE-2026-55460Snipe-IT is an IT asset/license management system. Prior to …7.1
- CVE-2026-55461Snipe-IT is an IT asset/license management system. Prior to …6.1
- CVE-2026-55462Snipe-IT is an IT asset/license management system. Prior to …4.3
- CVE-2026-55464Snipe-IT is an IT asset/license management system. Prior to …5.4
- CVE-2026-55466Snipe-IT is an IT asset/license management system. Prior to …8.7
Are you affected by CVE-2026-55455?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST