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Fencer Intel
critical 10.0

CVE-2026-82456 json

argocd-mcp 0.8.0 Authentication Bypass via Unauthenticated HTTP

published 3mo ago modified last mo. also EUVD-2026-68103 , GHSA-rp45-5x3v-48mr

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository argoproj-labs/mcp-for-argocd. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm argocd-mcp 0.9.0
  • argoproj-labs argocd-mcp 0.9.0

Is CVE-2026-82456 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
2mo ago

Exploit prediction

2.37% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/argoproj-labs/mcp-for-argocd/security/advisories/GHSA-rp45-5x3v-48mr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 10.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA 4.0 10.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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

Affected packages

ecosystem package affected fixed in
npm argocd-mcp
=0.8.0
0.9.0

Affected products

  • argoproj-labs argocd-mcp

Classification

Weakness
  • CWE-1327 Binding to an Unrestricted IP Address

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of argoproj-labs/mcp-for-argocd published their own advisory on GitHub. Reviewed sources take precedence over it.