{"answers":{"affected":"3 open source packages ship an affected version, including github.com/googleapis/mcp-toolbox.","exploited":"There is no known exploitation of CVE-2026-9739 in the wild and no public exploit code.","fix":"Upgrade github.com/googleapis/mcp-toolbox to 1.2.0 or later.","what":"CVE-2026-9739 is a critical vulnerability in Google MCP Toolbox for Databases, published on 27 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-9739 and fix it if it is affected.\n\nWhat it is: CVE-2026-9739 is a critical vulnerability in Google MCP Toolbox for Databases, published on 27 May 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2026-9739 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/googleapis/mcp-toolbox (Go): affected all versions; fixed in 1.2.0\n- github.com/googleapis/mcp-toolbox (Go): affected all versions; fixed in 1.2.0\n- github.com/googleapis/mcp-toolbox (Go): affected all versions; fixed in 1.2.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-9739/ (Markdown: https://insights.sbomify.com/CVE-2026-9739/index.md)","id":"CVE-2026-9739","markdown":"https://insights.sbomify.com/CVE-2026-9739/index.md","name":"CVE-2026-9739","record":{"aliases":["GHSA-7pf3-8xx7-rvhf","GO-2026-5870"],"analysis":{"component_type":"server_software","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"MCP Toolbox for Databases","requires_auth":"none","summary":"Attackers can bypass origin restrictions via DNS rebinding due to a hardcoded wildcard CORS header in the SSE handler.","user_interaction":"required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Google","cpe":[],"cvss":{"score":9.4,"severity":"critical","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H","version":"4.0"},"cwes":[{"id":"CWE-942","name":"Permissive Cross-domain Security Policy with Untrusted Domains"}],"description":"Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented `allowed-origins` and `allowed-hosts` flags to align with MCP security guidelines. However, the hardcoded `Access-Control-Allow-Origin: *` header in the SSE initialization handler was inadvertently retained. This vulnerability specifically impacts users connecting via Toolbox using SSE under specification v2024-11-05.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"MCP Toolbox for Databases vulnerable to DNS rebinding attacks","id":"CVE-2026-9739","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"security_feature_bypass","year":"2026"},"n_packages":3,"n_references":2,"next":{"headline":"Unbounded recursion in BSONColumn interleaved-reference causes pre-auth stack overflow","id":"CVE-2026-9740"},"packages":[{"ecosystem":"Go","fixed":["1.2.0"],"introduced":["0"],"last_affected":[],"package":"github.com/googleapis/mcp-toolbox","purl":null,"source":"GHSA-7pf3-8xx7-rvhf"},{"ecosystem":"Go","fixed":["1.2.0"],"introduced":["0"],"last_affected":[],"package":"github.com/googleapis/mcp-toolbox","purl":"pkg:golang/github.com/googleapis/mcp-toolbox","source":"GHSA-7pf3-8xx7-rvhf"},{"ecosystem":"Go","fixed":["1.2.0"],"introduced":["0"],"last_affected":[],"package":"github.com/googleapis/mcp-toolbox","purl":"pkg:golang/github.com/googleapis/mcp-toolbox","source":"GO-2026-5870"}],"prev":{"headline":"Cross-site scripting in Print, PDF \u0026 Email by PrintFriendly","id":"CVE-2026-9738"},"products":["MCP Toolbox for Databases"],"published":"2026-05-27","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-05-28","vendors":["Google"]},"summary":"Attackers can bypass origin restrictions via DNS rebinding due to a hardcoded wildcard CORS header in the SSE handler.","url":"https://insights.sbomify.com/CVE-2026-9739/"}