CVE-2026-34742

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-34742", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-30T19:17:10.224Z", "datePublished": "2026-04-02T18:32:34.781Z", "dateUpdated": "2026-07-15T01:04:01.603Z"}, "containers": {"cna": {"title": "Model Context Protocol Go SDK: DNS Rebinding Protection Disabled by Default for Servers Running on Localhost", "problemTypes": [{"descriptions": [{"cweId": "CWE-1188", "lang": "en", "description": "CWE-1188: Insecure Default Initialization of Resource", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 7.6, "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N", "version": "4.0"}}], "references": [{"name": "https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-xw59-hvm2-8pj6", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-xw59-hvm2-8pj6"}, {"name": "https://github.com/modelcontextprotocol/go-sdk/pull/760", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/go-sdk/pull/760"}, {"name": "https://github.com/modelcontextprotocol/go-sdk/commit/67bd3f2e2b53ce11a16db8d976cdb8ff1e986b6d", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/go-sdk/commit/67bd3f2e2b53ce11a16db8d976cdb8ff1e986b6d"}, {"name": "https://github.com/modelcontextprotocol/go-sdk/releases/tag/v1.4.0", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/go-sdk/releases/tag/v1.4.0"}], "affected": [{"vendor": "modelcontextprotocol", "product": "go-sdk", "versions": [{"version": "< 1.4.0", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-04-02T18:32:34.781Z"}, "descriptions": [{"lang": "en", "value": "The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.0, the Model Context Protocol (MCP) Go SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication with StreamableHTTPHandler or SSEHandler, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. This issue has been patched in version 1.4.0."}], "source": {"advisory": "GHSA-xw59-hvm2-8pj6", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-04-03T15:58:40.335119Z", "id": "CVE-2026-34742", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-03T15:59:37.091Z"}}, {"affected": [{"collectionURL": "https://catalog.redhat.com/software/containers/", "cpes": ["cpe:/a:redhat:openshift_devspaces:3.28::el9"], "defaultStatus": "affected", "packageName": "devspaces/udi-rhel9", "product": "Red Hat OpenShift Dev Spaces 3.28", "vendor": "Red Hat", "versions": [{"lessThan": "*", "status": "unaffected", "version": "1779829736", "versionType": "rpm"}]}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "migration-toolkit-virtualization/mtv-cli-download-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-api-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-cli-download-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-controller-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-operator-bundle", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:openshift_lightspeed"], "defaultStatus": "unaffected", "packageName": "openshift-lightspeed/openshift-mcp-server-rhel9", "product": "OpenShift Lightspeed", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:serverless:1"], "defaultStatus": "affected", "packageName": "openshift-serverless-1/kn-client-kn-rhel9", "product": "OpenShift Serverless", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:serverless:1"], "defaultStatus": "affected", "packageName": "openshift-serverless-1/kn-plugin-func-func-util-rhel9", "product": "OpenShift Serverless", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:openshift_ai"], "defaultStatus": "unaffected", "packageName": "rhoai/odh-mod-arch-gen-ai-rhel9", "product": "Red Hat OpenShift AI (RHOAI)", "vendor": "Red Hat"}], "datePublic": "2026-04-02T18:32:34.781Z", "descriptions": [{"lang": "en", "value": "A flaw was found in the Model Context Protocol (MCP) Go SDK. When an HTTP-based MCP server is run on localhost without authentication, a malicious website can exploit a DNS rebinding vulnerability. This allows the attacker to bypass same-origin policy restrictions and send requests to the local MCP server. Consequently, an attacker could invoke tools or access resources exposed by the MCP server on behalf of the user."}], "metrics": [{"other": {"content": {"namespace": "https://access.redhat.com/security/updates/classification/", "value": "Important"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N", "version": "3.1"}, "format": "CVSS"}], "problemTypes": [{"descriptions": [{"cweId": "CWE-1188", "description": "Initialization of a Resource with an Insecure Default", "lang": "en", "type": "CWE"}]}], "references": [{"tags": ["vdb-entry", "x_refsource_REDHAT"], "url": "https://access.redhat.com/security/cve/CVE-2026-34742"}, {"name": "RHBZ#2454608", "tags": ["issue-tracking", "x_refsource_REDHAT"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2454608"}, {"tags": ["x_sadp-csaf-vex"], "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34742.json"}, {"tags": ["vendor-advisory", "x_refsource_REDHAT"], "url": "https://access.redhat.com/errata/RHSA-2026:21772"}], "solutions": [{"lang": "en", "value": "RHSA-2026:21772: Red Hat OpenShift Dev Spaces 3.28"}], "timeline": [{"lang": "en", "time": "2026-04-02T19:06:39.830Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-04-02T18:32:34.781Z", "value": "Made public."}], "title": "github.com/modelcontextprotocol/go-sdk: Model Context Protocol (MCP) Go SDK: DNS rebinding vulnerability allows unauthorized access", "workarounds": [{"lang": "en", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}], "x_adpType": "supplier", "x_generator": {"engine": "sadp-cli 1.0.0"}, "providerMetadata": {"orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "shortName": "redhat-SADP", "dateUpdated": "2026-07-15T01:04:01.603Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "github.com/modelcontextprotocol/go-sdk: Model Context Protocol (MCP) Go SDK: DNS rebinding vulnerability allows unauthorized access", "metrics": [{"other": {"type": "Red Hat severity rating", "content": {"value": "Important", "namespace": "https://access.redhat.com/security/updates/classification/"}}}, {"format": "CVSS", "cvssV3_1": {"scope": "CHANGED", "version": "3.1", "baseScore": 8, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "HIGH", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}}], "affected": [{"cpes": ["cpe:/a:redhat:openshift_devspaces:3.28::el9"], "vendor": "Red Hat", "product": "Red Hat OpenShift Dev Spaces 3.28", "versions": [{"status": "unaffected", "version": "1779829736", "lessThan": "*", "versionType": "rpm"}], "packageName": "devspaces/udi-rhel9", "collectionURL": "https://catalog.redhat.com/software/containers/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "vendor": "Red Hat", "product": "Migration Toolkit for Virtualization", "packageName": "migration-toolkit-virtualization/mtv-cli-download-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "vendor": "Red Hat", "product": "Migration Toolkit for Virtualization", "packageName": "mtv-candidate/mtv-api-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "vendor": "Red Hat", "product": "Migration Toolkit for Virtualization", "packageName": "mtv-candidate/mtv-cli-download-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "vendor": "Red Hat", "product": "Migration Toolkit for Virtualization", "packageName": "mtv-candidate/mtv-controller-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "vendor": "Red Hat", "product": "Migration Toolkit for Virtualization", "packageName": "mtv-candidate/mtv-operator-bundle", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:openshift_lightspeed"], "vendor": "Red Hat", "product": "OpenShift Lightspeed", "packageName": "openshift-lightspeed/openshift-mcp-server-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/a:redhat:serverless:1"], "vendor": "Red Hat", "product": "OpenShift Serverless", "packageName": "openshift-serverless-1/kn-client-kn-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:serverless:1"], "vendor": "Red Hat", "product": "OpenShift Serverless", "packageName": "openshift-serverless-1/kn-plugin-func-func-util-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/a:redhat:openshift_ai"], "vendor": "Red Hat", "product": "Red Hat OpenShift AI (RHOAI)", "packageName": "rhoai/odh-mod-arch-gen-ai-rhel9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}], "timeline": [{"lang": "en", "time": "2026-04-02T19:06:39.830Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-04-02T18:32:34.781Z", "value": "Made public."}], "solutions": [{"lang": "en", "value": "RHSA-2026:21772: Red Hat OpenShift Dev Spaces 3.28"}], "x_adpType": "supplier", "datePublic": "2026-04-02T18:32:34.781Z", "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-34742", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2454608", "name": "RHBZ#2454608", "tags": ["issue-tracking", "x_refsource_REDHAT"]}, {"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34742.json", "tags": ["x_sadp-csaf-vex"]}, {"url": "https://access.redhat.com/errata/RHSA-2026:21772", "tags": ["vendor-advisory", "x_refsource_REDHAT"]}], "workarounds": [{"lang": "en", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}], "x_generator": {"engine": "sadp-cli 1.0.0"}, "descriptions": [{"lang": "en", "value": "A flaw was found in the Model Context Protocol (MCP) Go SDK. When an HTTP-based MCP server is run on localhost without authentication, a malicious website can exploit a DNS rebinding vulnerability. This allows the attacker to bypass same-origin policy restrictions and send requests to the local MCP server. Consequently, an attacker could invoke tools or access resources exposed by the MCP server on behalf of the user."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-1188", "description": "Initialization of a Resource with an Insecure Default"}]}], "providerMetadata": {"orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "shortName": "redhat-SADP", "dateUpdated": "2026-07-15T01:04:01.603Z"}}, {"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-34742", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-04-03T15:58:40.335119Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-04-03T15:59:03.748Z"}}], "cna": {"title": "Model Context Protocol Go SDK: DNS Rebinding Protection Disabled by Default for Servers Running on Localhost", "source": {"advisory": "GHSA-xw59-hvm2-8pj6", "discovery": "UNKNOWN"}, "metrics": [{"cvssV4_0": {"version": "4.0", "baseScore": 7.6, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N", "userInteraction": "PASSIVE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH"}}], "affected": [{"vendor": "modelcontextprotocol", "product": "go-sdk", "versions": [{"status": "affected", "version": "< 1.4.0"}]}], "references": [{"url": "https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-xw59-hvm2-8pj6", "name": "https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-xw59-hvm2-8pj6", "tags": ["x_refsource_CONFIRM"]}, {"url": "https://github.com/modelcontextprotocol/go-sdk/pull/760", "name": "https://github.com/modelcontextprotocol/go-sdk/pull/760", "tags": ["x_refsource_MISC"]}, {"url": "https://github.com/modelcontextprotocol/go-sdk/commit/67bd3f2e2b53ce11a16db8d976cdb8ff1e986b6d", "name": "https://github.com/modelcontextprotocol/go-sdk/commit/67bd3f2e2b53ce11a16db8d976cdb8ff1e986b6d", "tags": ["x_refsource_MISC"]}, {"url": "https://github.com/modelcontextprotocol/go-sdk/releases/tag/v1.4.0", "name": "https://github.com/modelcontextprotocol/go-sdk/releases/tag/v1.4.0", "tags": ["x_refsource_MISC"]}], "descriptions": [{"lang": "en", "value": "The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.0, the Model Context Protocol (MCP) Go SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication with StreamableHTTPHandler or SSEHandler, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. This issue has been patched in version 1.4.0."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-1188", "description": "CWE-1188: Insecure Default Initialization of Resource"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-04-02T18:32:34.781Z"}}}, "cveMetadata": {"cveId": "CVE-2026-34742", "state": "PUBLISHED", "dateUpdated": "2026-07-15T01:04:01.603Z", "dateReserved": "2026-03-30T19:17:10.224Z", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "datePublished": "2026-04-02T18:32:34.781Z", "assignerShortName": "GitHub_M"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"product": "go-sdk", "vendor": "modelcontextprotocol", "versions": [{"status": "affected", "version": "< 1.4.0"}]}], "source": "security-advisories@github.com"}, {"affectedData": [{"collectionURL": "https://catalog.redhat.com/software/containers/", "cpes": ["cpe:/a:redhat:openshift_devspaces:3.28::el9"], "defaultStatus": "affected", "packageName": "devspaces/udi-rhel9", "product": "Red Hat OpenShift Dev Spaces 3.28", "vendor": "Red Hat", "versions": [{"lessThan": "*", "status": "unaffected", "version": "1779829736", "versionType": "rpm"}]}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "migration-toolkit-virtualization/mtv-cli-download-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-api-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-cli-download-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-controller-rhel9", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:migration_toolkit_virtualization:2"], "defaultStatus": "affected", "packageName": "mtv-candidate/mtv-operator-bundle", "product": "Migration Toolkit for Virtualization", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:openshift_lightspeed"], "defaultStatus": "unaffected", "packageName": "openshift-lightspeed/openshift-mcp-server-rhel9", "product": "OpenShift Lightspeed", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:serverless:1"], "defaultStatus": "affected", "packageName": "openshift-serverless-1/kn-client-kn-rhel9", "product": "OpenShift Serverless", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:serverless:1"], "defaultStatus": "affected", "packageName": "openshift-serverless-1/kn-plugin-func-func-util-rhel9", "product": "OpenShift Serverless", "vendor": "Red Hat"}, {"collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "cpes": ["cpe:/a:redhat:openshift_ai"], "defaultStatus": "unaffected", "packageName": "rhoai/odh-mod-arch-gen-ai-rhel9", "product": "Red Hat OpenShift AI (RHOAI)", "vendor": "Red Hat"}], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:lfprojects:mcp_go_sdk:*:*:*:*:*:*:*:*", "matchCriteriaId": "92CB3EED-2D8E-4ADC-BD05-2A14C13CA7DA", "versionEndExcluding": "1.4.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.0, the Model Context Protocol (MCP) Go SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication with StreamableHTTPHandler or SSEHandler, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. This issue has been patched in version 1.4.0."}, {"lang": "es", "value": "El SDK Go de MCP utilizaba el encoding/json est\u00e1ndar de Go. Antes de la versi\u00f3n 1.4.0, el SDK Go del Protocolo de Contexto del Modelo (MCP) no habilita la protecci\u00f3n contra el rebinding de DNS por defecto para servidores basados en HTTP. Cuando un servidor MCP basado en HTTP se ejecuta en localhost sin autenticaci\u00f3n con StreamableHTTPHandler o SSEHandler, un sitio web malicioso podr\u00eda explotar el rebinding de DNS para eludir las restricciones de la pol\u00edtica de mismo origen y enviar solicitudes al servidor MCP local. Esto podr\u00eda permitir a un atacante invocar herramientas o acceder a recursos expuestos por el servidor MCP en nombre del usuario en esas circunstancias limitadas. Este problema ha sido parcheado en la versi\u00f3n 1.4.0."}], "id": "CVE-2026-34742", "lastModified": "2026-07-24T21:10:00.143", "metrics": {"cvssMetricV31": [{"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"}, {"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 8.0, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 1.6, "impactScore": 5.8, "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 7.6, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-34742", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-04-03T15:58:40.335119Z", "version": "2.0.3"}}]}, "published": "2026-04-02T19:21:33.023", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/modelcontextprotocol/go-sdk/commit/67bd3f2e2b53ce11a16db8d976cdb8ff1e986b6d"}, {"source": "security-advisories@github.com", "tags": ["Issue Tracking", "Patch"], "url": "https://github.com/modelcontextprotocol/go-sdk/pull/760"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/modelcontextprotocol/go-sdk/releases/tag/v1.4.0"}, {"source": "security-advisories@github.com", "tags": ["Vendor Advisory"], "url": "https://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-xw59-hvm2-8pj6"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "url": "https://access.redhat.com/errata/RHSA-2026:21772"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "url": "https://access.redhat.com/security/cve/CVE-2026-34742"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2454608"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34742.json"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1188"}], "source": "security-advisories@github.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "CWE-1188"}], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "type": "Secondary"}]}

{"bugzilla": {"description": "github.com/modelcontextprotocol/go-sdk: Model Context Protocol (MCP) Go SDK: DNS rebinding vulnerability allows unauthorized access", "id": "2454608", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2454608"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.0", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N", "status": "draft"}, "cwe": "CWE-1188", "details": ["A flaw was found in the Model Context Protocol (MCP) Go SDK. When an HTTP-based MCP server is run on localhost without authentication, a malicious website can exploit a DNS rebinding vulnerability. This allows the attacker to bypass same-origin policy restrictions and send requests to the local MCP server. Consequently, an attacker could invoke tools or access resources exposed by the MCP server on behalf of the user."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2026-34742", "package_state": [{"cpe": "cpe:/a:redhat:migration_toolkit_virtualization:2", "fix_state": "Affected", "package_name": "migration-toolkit-virtualization/mtv-cli-download-rhel9", "product_name": "Migration Toolkit for Virtualization"}, {"cpe": "cpe:/a:redhat:migration_toolkit_virtualization:2", "fix_state": "Affected", "package_name": "mtv-candidate/mtv-api-rhel9", "product_name": "Migration Toolkit for Virtualization"}, {"cpe": "cpe:/a:redhat:migration_toolkit_virtualization:2", "fix_state": "Affected", "package_name": "mtv-candidate/mtv-cli-download-rhel9", "product_name": "Migration Toolkit for Virtualization"}, {"cpe": "cpe:/a:redhat:migration_toolkit_virtualization:2", "fix_state": "Affected", "package_name": "mtv-candidate/mtv-controller-rhel9", "product_name": "Migration Toolkit for Virtualization"}, {"cpe": "cpe:/a:redhat:migration_toolkit_virtualization:2", "fix_state": "Affected", "package_name": "mtv-candidate/mtv-operator-bundle", "product_name": "Migration Toolkit for Virtualization"}, {"cpe": "cpe:/a:redhat:openshift_lightspeed", "fix_state": "Affected", "package_name": "openshift-lightspeed/openshift-mcp-server-rhel9", "product_name": "OpenShift Lightspeed"}, {"cpe": "cpe:/a:redhat:serverless:1", "fix_state": "Affected", "package_name": "openshift-serverless-1/kn-client-kn-rhel9", "product_name": "OpenShift Serverless"}, {"cpe": "cpe:/a:redhat:serverless:1", "fix_state": "Affected", "package_name": "openshift-serverless-1/kn-plugin-func-func-util-rhel9", "product_name": "OpenShift Serverless"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Affected", "package_name": "rhoai/odh-mod-arch-gen-ai-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_devspaces:3", "fix_state": "Affected", "package_name": "devspaces/udi-rhel9", "product_name": "Red Hat OpenShift Dev Spaces"}], "public_date": "2026-04-02T18:32:34Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-34742\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-34742\nhttps://github.com/modelcontextprotocol/go-sdk/commit/67bd3f2e2b53ce11a16db8d976cdb8ff1e986b6d\nhttps://github.com/modelcontextprotocol/go-sdk/pull/760\nhttps://github.com/modelcontextprotocol/go-sdk/releases/tag/v1.4.0\nhttps://github.com/modelcontextprotocol/go-sdk/security/advisories/GHSA-xw59-hvm2-8pj6"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.4.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "go-sdk", "source": "cna", "vendor": "modelcontextprotocol"}, "product": "go-sdk", "vendor": "modelcontextprotocol"}], "analysis": {"en": {"generated_at": "2026-04-03T22:26:18.349075+00:00", "value": {"mitigation_remediation": ["Update the Model Context Protocol Go SDK to version 1.4.0 or later to enable DNS rebinding protection by default."], "summary": {"action": "Immediate Patch", "impact": "Remote code execution via DNS rebinding"}, "threat_synthesis": {"affected_systems": "All installations of the Model Context Protocol Go SDK earlier than version 1.4.0 that host an HTTP server on localhost using StreamableHTTPHandler or SSEHandler are affected. The vulnerability applies only when the server is exposed to the same machine and no authentication is required.", "description_and_impact": "The Model Context Protocol Go SDK fails to enable DNS rebinding protection by default on HTTP-based servers that run on localhost. When a local server is launched without authentication, a malicious website can perform DNS rebinding to trick the user\u2019s browser into sending requests to the local MCP server, thereby bypassing the same\u2011origin policy and allowing the attacker to invoke server tools or access data exposed by the server. This represents an information\u2011and\u2011execution\u2011type vulnerability that can provide the attacker with the same level of access as the local user.", "risk_and_exploitability": "The CVSS score of 7.6 indicates a high severity and the EPSS score of less than 1% suggests that the likelihood of exploitation is currently low, though the vulnerability is not listed in the CISA KEV catalog. An attacker would need to lure the targeted user to a malicious web page, perform a DNS rebinding attack to point a domain to the local address, and then send requests to the local MCP server. Successful exploitation would grant the attacker the same privileges as the user running the server, potentially allowing execution of arbitrary code or access to sensitive resources."}}}}, "created": "2026-04-03T07:31:43.887228+00:00", "updated": "2026-04-07T07:55:31.481011+00:00", "vendors": ["modelcontextprotocol", "modelcontextprotocol$PRODUCT$go-sdk"]}