๐Ÿ” CVE Alert

CVE-2026-81094

CRITICAL 9.1

mcp-router CLI before 0.6.3 Binds the MCP Aggregator to All Interfaces Without Requiring Authentication

CVSS Score
9.1
EPSS Score
0.0%
EPSS Percentile
0th

The mcp-router CLI served its MCP aggregator on every interface and enforced authentication only when the operator asked for it. The serve command in apps/cli/src/commands/serve.ts defaulted its host to the all-interfaces address on a fixed port, and required a token only when the corresponding flag was supplied, so a default invocation exposed the aggregator, and every MCP server it fronted, to anyone able to reach the port. Release 0.6.3 defaults the host to the loopback address and refuses to start without a token whenever the host it is given is not a loopback address; no earlier release carries either check.

CWE CWE-306
Vendor mcp-router
Product mcp-router
Published Aug 27, 2026
Last Updated Aug 27, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

Affected Versions

mcp-router / mcp-router
0 < 0.6.3

References

NVD โ†— CVE.org โ†— EPSS Data โ†—
github.com: https://github.com/mcp-router/mcp-router github.com: https://github.com/mcp-router/mcp-router/security/advisories/GHSA-rx55-5c7h-r56r github.com: https://github.com/mcp-router/mcp-router/commit/4c4642cfd274097ec8b33ecd3047390829c79d35 github.com: https://github.com/mcp-router/mcp-router/blob/v0.6.3/apps/cli/src/commands/serve.ts#L105 vulncheck.com: https://www.vulncheck.com/advisories/mcp-router-cli-before-0.6.3-binds-the-mcp-aggregator-to-all-interfaces-without-requiring-authentication

Credits

Yotam Perkal (Pluto Security)