CVE-2026-29791: Agentgateway: Missing parameter sanitization in MCP to OpenAPI conversion
Summary
When converting MCP tools/call request to OpenAPI request, input path, query, and header values are not sanitized.
Details
When using the MCP to OpenAPI feature, the proxy lacks proper sanitization of input parameters in the MCP call, allowing: Injection of additional path or query parameters. Injection of additional headers.
Impacted Versions
This vulnerability is fixed in Agentgateway v0.12.0+. Users on older versions are recommended to upgrade to v0.12.0+.
This feature only impacts usage of the MCP to OpenAPI feature
Credits
Agentgateway extends its thanks to @spacewander for the report!
Other sources
Agentgateway is an open source data plane for agentic AI connectivity within or across any agent framework or environment. Prior to version 0.12.0, when converting MCP tools/call request to OpenAPI request, input path, query, and header values are not sanitized. This issue has been patched in version 0.12.0.
— MITRE
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-29791?
The severity of CVE-2026-29791 is rated as medium due to the missing parameter sanitization in the MCP to OpenAPI conversion.
How do I fix CVE-2026-29791?
To fix CVE-2026-29791, ensure that parameter sanitization is implemented for input path, query, and header values during the MCP to OpenAPI conversion.
Which versions of Agentgateway are affected by CVE-2026-29791?
CVE-2026-29791 affects Agentgateway versions prior to 0.12.0.
What kind of vulnerability is CVE-2026-29791?
CVE-2026-29791 is classified as an input validation vulnerability due to missing sanitization.
Is CVE-2026-29791 a critical vulnerability?
No, CVE-2026-29791 is not considered a critical vulnerability, but it requires attention to prevent potential security risks.