mcp-router up to 0.6.2 CLI serve.ts access control

CVSS Meta Temp Score
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CTI Interest Score
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8.0$0-$5k0.32-

Summaryinfo

A vulnerability has been found in mcp-router up to 0.6.2 and classified as critical. The affected element is an unknown function of the file apps/cli/src/commands/serve.ts of the component CLI. This manipulation causes access control. The identification of this vulnerability is CVE-2026-81094. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in mcp-router up to 0.6.2. It has been declared as critical. Affected by this vulnerability is an unknown part of the file apps/cli/src/commands/serve.ts of the component CLI. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-81094 since 08/26/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 0.6.3 eliminates this vulnerability. Applying the patch 4c4642cfd274097ec8b33ecd3047390829c79d35 is able to eliminate this problem.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 8.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.1
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: mcp-router 0.6.3
Patch: 4c4642cfd274097ec8b33ecd3047390829c79d35

Timelineinfo

08/26/2026 CVE reserved
08/27/2026 +1 days Advisory disclosed
08/27/2026 +0 days VulDB entry created
08/27/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-81094 (🔒)
GCVE (CVE): GCVE-0-2026-81094
GCVE (VulDB): GCVE-100-396259

Entryinfo

Created: 08/27/2026 20:02
Changes: 08/27/2026 20:02 (78)
Complete: 🔍
Cache ID: 216::103

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