{"id":"CVE-2026-29791","aliases":["GHSA-v2x6-wwfw-r2rq"],"url":"https://o3.security/vulnerability/CVE-2026-29791","summary":"Agentgateway: Missing parameter sanitization in MCP to OpenAPI conversion","details":"### Summary\n\nWhen converting MCP `tools/call` request to OpenAPI request, input path, query, and header values are not sanitized.\n\n### Details\n\nWhen using the [MCP to OpenAPI](https://agentgateway.dev/docs/standalone/latest/mcp/connect/openapi/) feature, the proxy lacks proper sanitization of input parameters in the MCP call, allowing:\n* Injection of additional path or query parameters.\n* Injection of additional headers.\n\n### Impacted Versions\n\nThis vulnerability is fixed in Agentgateway v0.12.0+. Users on older versions are recommended to upgrade to v0.12.0+.\n\nThis feature only impacts usage of the [MCP to OpenAPI](https://agentgateway.dev/docs/standalone/latest/mcp/connect/openapi/) feature\n\n### Credits\n\nAgentgateway extends its thanks to @spacewander for the report!","published":"2026-03-06T20:39:40.852Z","modified":"2026-08-12T03:51:10.614339300Z","cvss":{"score":4.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/agentgateway/agentgateway","fixedVersion":"0.12.0"}],"fix":{"url":"https://github.com/agentgateway/agentgateway/commit/9a5287569d892e77a8be8c3bb7bf3d7744244274","label":"agentgateway/agentgateway@9a52875"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/29xxx/CVE-2026-29791.json"},{"type":"ADVISORY","url":"https://github.com/agentgateway/agentgateway/security/advisories/GHSA-v2x6-wwfw-r2rq"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-29791"},{"type":"WEB","url":"https://github.com/agentgateway/agentgateway/commit/9a5287569d892e77a8be8c3bb7bf3d7744244274"},{"type":"PACKAGE","url":"https://github.com/agentgateway/agentgateway"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:10.614339300Z"}}