{"id":"CVE-2026-14539","aliases":["EUVD-2026-51373","GHSA-623p-8r6m-hwc6"],"status":"published","title":"Denial of Service via Unrestricted Payload Buffering in MCP Toolbox","description":"An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.","severity":{"version":"4.0","score":6.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00238,"percentile":0.14865,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-770"],"published":"2026-07-31T01:45:35Z","modified":"2026-10-28T02:30:23Z","products":[{"vendor":"google","product":"mcp-toolbox"},{"vendor":"google","product":"mcp_toolbox_for_databases"}],"references":[{"url":"https://github.com/googleapis/mcp-toolbox/pull/3216","tags":["Issue Tracking","Patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-14539","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-623p-8r6m-hwc6"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/14xxx/CVE-2026-14539.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-14539","title":"Denial of Service via Unrestricted Payload Buffering in MCP Toolbox","description":"An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.","status":"published","published":"2026-07-31T01:45:35.468Z","modified":"2026-07-31T16:11:48.201Z","cvss":[{"version":"4.0","score":6.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U","level":"medium","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T13:38:32.13011Z"}],"euvd":[{"id":"EUVD-2026-51373","description":"An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.","status":"published","published":"2026-07-31T01:45:35Z","modified":"2026-07-31T16:11:48Z","cvss":[{"version":"4.0","score":6.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U","level":"medium"}],"updated_at":"2026-11-02T18:02:25.856077Z"}],"ghsa":[{"id":"GHSA-623p-8r6m-hwc6","title":"An allocation of resources without limits vulnerability in the HTTP handler component of Google...","description":"An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.","status":"published","published":"2026-07-31T03:31:16Z","modified":"2026-08-08T00:31:10Z","cvss":[{"version":"4.0","score":6.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/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","level":"medium"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:10:12.306859Z"}],"nvd":[{"id":"CVE-2026-14539","description":"An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.","status":"published","published":"2026-07-31T02:16:28.92Z","modified":"2026-10-23T23:10:00.157Z","cvss":[{"version":"4.0","score":6.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/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","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:12:33.955581Z"}],"osv":[{"id":"CVE-2026-14539","title":"Denial of Service via Unrestricted Payload Buffering in MCP Toolbox","description":"An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.","status":"published","published":"2026-07-31T01:45:35.468Z","modified":"2026-10-28T02:30:23.360414362Z","cvss":[{"version":"4.0","score":6.6,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:44:57.354194Z"}]}}