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Fencer Vulns
critical 9.9

CVE-2026-79748 json

MCPHub: Authenticated non-admin user achieves RCE via POST /api/servers (missing authorization on stdio command/args)

published 2026-08-31 2 mo ago modified 2026-09-08 2 mo ago also EUVD-2026-68686

cvss
9.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

MCPHub is a unified hub for centrally managing and dynamically orchestrating multiple MCP servers/APIs into separate endpoints with flexible routing strategies. Prior to version 0.12.15, the POST /api/servers and PUT /api/servers/:name endpoints in MCPHub create/update MCP server configurations and then immediately spawn the configured stdio process via child_process.spawn. Authentication is required, but there is no authorization check restricting these endpoints to admins, and there is no allowlist/sanitization on the command and args fields. As a result, any authenticated non-admin user can submit a server configuration with command:"/bin/sh" (or any other binary) and arbitrary args, causing MCPHub to execute the attacker-controlled process as the MCPHub server's OS user (commonly root in the published Docker image and in npx/systemd deployments). This issue has been patched in version 0.12.15.

Patch / fix

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/samanhappy/mcphub/security/advisories/GHSA-mx89-jjx9-gjr8 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • samanhappy mcphub

Classification

Weakness

References

Sources

Fencer Vulns 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.