Vulnerability · Published Aug 29, 2026 · Assigned by VulnCheck

CVE-2026-82456argocd-mcp 0.8.0 Authentication Bypass via Unauthenticated HTTP

Critical 10.0

In plain English

A critical-severity security flaw in argocd-mcp from argoproj-labs. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 2.4% (higher than 84% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei.

Severity (CVSS 3.1)10.0Critical

Exploit odds (30 days)2.4%top 16.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack tooling1Nuclei

Official description

argocd-mcp 0.8.0 binds its HTTP transport to every network interface and accepts MCP sessions without requiring caller credentials when ARGOCD_API_TOKEN is configured. Attackers who can reach the listener can invoke the full tool surface using the operator's stored token to create applications, request syncs, and modify Argo CD resources.

Affected products (as reported)

Vendor	Product	Versions
argoproj-labs	argocd-mcp	0.8.0 – before 0.9.0

Weakness: CWE-1327 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References

GitHub Security Advisory (GHSA-rp45-5x3v-48mr) vendor-advisory
https://github.com/argoproj-labs/mcp-for-argocd product
VulnCheck Advisory: argocd-mcp 0.8.0 Authentication Bypass via Unauthenticated HTTP third-party-advisory