CVE-2026-35577

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{"affected": [{"affectedData": [{"product": "apollo-mcp-server", "vendor": "apollographql", "versions": [{"status": "affected", "version": "< 1.7.0"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:apollographql:apollo_mcp_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "8F975CB2-D811-487F-BBC4-D66D069AACBD", "versionEndExcluding": "1.7.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Apollo MCP Server is a Model Context Protocol server that exposes GraphQL operations as MCP tools. Prior to version 1.7.0, the Apollo MCP Server did not validate the Host header on incoming HTTP requests when using StreamableHTTP transport. In configurations where an HTTP-based MCP server is run on localhost without additional authentication or network-level controls, this could potentially allow a malicious website\u2014visited by a user running the server locally\u2014to use DNS rebinding techniques to bypass same-origin policy restrictions and issue requests to the local MCP server. If successfully exploited, this could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the local user. This issue is limited to HTTP-based transport modes (StreamableHTTP). It does not affect servers using stdio transport. The practical risk is further reduced in deployments that use authentication, network-level access controls, or are not bound to localhost. This vulnerability is fixed in 1.7.0."}, {"lang": "es", "value": "Apollo MCP Server es un servidor de Protocolo de Contexto de Modelo que expone operaciones GraphQL como herramientas MCP. Antes de la versi\u00f3n 1.7.0, el servidor Apollo MCP no validaba el encabezado Host en las solicitudes HTTP entrantes cuando utilizaba el transporte StreamableHTTP. En configuraciones donde un servidor MCP basado en HTTP se ejecuta en localhost sin autenticaci\u00f3n adicional o controles a nivel de red, esto podr\u00eda permitir potencialmente que un sitio web malicioso -visitado por un usuario que ejecuta el servidor localmente- utilice t\u00e9cnicas de reencuadernaci\u00f3n de DNS para eludir las restricciones de la pol\u00edtica del mismo origen y emitir solicitudes al servidor MCP local. Si se explota con \u00e9xito, esto podr\u00eda permitir a un atacante invocar herramientas o acceder a recursos expuestos por el servidor MCP en nombre del usuario local. Este problema se limita a los modos de transporte basados en HTTP (StreamableHTTP). No afecta a los servidores que utilizan el transporte stdio. El riesgo pr\u00e1ctico se reduce a\u00fan m\u00e1s en implementaciones que utilizan autenticaci\u00f3n, controles de acceso a nivel de red o no est\u00e1n vinculadas a localhost. Esta vulnerabilidad se corrige en la versi\u00f3n 1.7.0."}], "id": "CVE-2026-35577", "lastModified": "2026-10-26T22:10:00.163", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.8, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 1.6, "impactScore": 5.2, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.2, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-35577", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-04-13T15:05:51.571445Z", "version": "2.0.3"}}]}, "published": "2026-04-09T20:16:25.987", "references": [{"source": "security-advisories@github.com", "tags": ["Issue Tracking"], "url": "https://github.com/apollographql/apollo-mcp-server/pull/602"}, {"source": "security-advisories@github.com", "tags": ["Issue Tracking"], "url": "https://github.com/apollographql/apollo-mcp-server/pull/635"}, {"source": "security-advisories@github.com", "tags": ["Mitigation", "Vendor Advisory"], "url": "https://github.com/apollographql/apollo-mcp-server/security/advisories/GHSA-wqrj-vp8w-f8vh"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-346"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.7.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "product": "apollo-mcp-server", "vendor": "apollographql"}], "analysis": {"en": {"generated_at": "2026-04-09T21:22:23.933900+00:00", "value": {"mitigation_remediation": ["Upgrade Apollo MCP Server to version 1.7.0 or later", "If upgrade is not immediately possible, restrict the MCP server to non\u2011localhost interfaces or enforce authentication and network\u2011level access controls", "Consider disabling StreamableHTTP transport or using stdio transport to eliminate the host\u2011header validation issue"], "summary": {"action": "Patch", "impact": "Unauthorized Access"}, "threat_synthesis": {"affected_systems": "Apollo MCP Server deployments running the StreamableHTTP transport before version 1.7.0 and bound to localhost without additional authentication or network\u2011level controls are affected. Servers employing the stdio transport are not impacted, nor are those using authentication or external access restrictions.", "description_and_impact": "The vulnerability arises from the absence of Host header validation on HTTP requests received by certain transports of Apollo MCP Server. This oversight permits a malicious site to craft requests with a forged Host header, enabling DNS rebinding attacks that circumvent same-origin policy limitations. An attacker exploiting this flaw can invoke GraphQL\u2011based tools or access other resources that the local MCP server exposes, effectively performing actions on behalf of the local user. The weakness aligns with CWE\u2011346, which focuses on lack of input validation for request headers.", "risk_and_exploitability": "The CVSS score of 6.8 indicates a moderate risk level; EPSS data is not available and the vulnerability is not listed in the KEV catalog. Exploitation requires that a user visits a malicious website while the MCP server is running locally, leveraging DNS rebinding to supply a forged Host header. With the attacker\u2019s ability to execute tools or retrieve resources locally, the impact could be significant for confidentiality, integrity, and availability of data or processes exposed by the MCP server. Deployments that restrict network interfaces or enforce authentication significantly reduce exploitable surface area."}}}}, "created": "2026-04-10T08:38:45.938052+00:00", "updated": "2026-04-10T09:29:29.069803+00:00", "vendors": ["apollographql", "apollographql$PRODUCT$apollo-mcp-server"]}