CVE-2026-81094
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://github.com/mcp-router/mcp-router
- https://github.com/mcp-router/mcp-router/blob/v0.6.3/apps/cli/src/commands/serve.ts#L105
- https://github.com/mcp-router/mcp-router/commit/4c4642cfd274097ec8b33ecd3047390829c79d35
- https://github.com/mcp-router/mcp-router/security/advisories/GHSA-rx55-5c7h-r56r
- https://www.vulncheck.com/advisories/mcp-router-cli-before-0.6.3-binds-the-mcp-aggregator-to-all-interfaces-without-requiring-authentication
CWEs
CWE-306
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.