CVE-2026-79746

MCPHub: Server-scoped bearer key gains access to an entire group via partial (any-overlap) server matching

HIGH
8.1
CVSS Score
Published: August 31, 2026 at 05:55 PM UTC
Updated: September 8, 2026 at 09:19 PM UTC
1 product affected across 1 vendorMCPHub

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Severity
HIGH8.1
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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 1.0.31, when a bearer key with accessType: 'servers' (or 'custom') is used against a group route, isBearerKeyAllowedForRequest grants access to the entire group as long as any single server in that group appears in the key's allowedServers list — not only when every server the key is scoped to matches, and critically, without ever re-checking allowedServers again once the group-level connection is authorized. A key explicitly scoped to one specific server therefore also grants full access to every other server that happens to share a group with it, including servers the key was never authorized for. This issue has been patched in version 1.0.31.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.0.31
Affected range stops below 1.0.31, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-863

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