CVE-2026-29791
Agentgateway is missing parameter sanitization in MCP to OpenAPI conversion
Description
### 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](https://agentgateway.dev/docs/standalone/latest/mcp/connect/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](https://agentgateway.dev/docs/standalone/latest/mcp/connect/openapi/) feature ### Credits Agentgateway extends its thanks to @spacewander for the report!
How to fix CVE-2026-29791
To remediate CVE-2026-29791, upgrade the affected package to a fixed version below.
- —upgrade to 0.12.0 or later
Is CVE-2026-29791 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 0.12.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM4.9 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N |