CVE-2026-29791: Github.com/agentgateway/agentgateway Agentgateway Is Missing Parameter Sanitization Vulnerability
MODERATECVE-2026-29791 is a MODERATE (CVSS 4.9) agentgateway is missing parameter sanitization vulnerability (CWE-20: Improper Input Validation) affecting Github.com/agentgateway/agentgateway libraries in the Go ecosystem. The issue involves agentgateway is missing parameter sanitization in mcp to openapi conversion. Remediation is available by upgrading affected packages to version 0.12.0.
CVE-2026-29791 at a Glance
Security Impact
CVSS: 4.9
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N).
How to Fix CVE-2026-29791
To remediate this vulnerability, upgrade all affected Github.com/agentgateway/agentgateway dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/agentgateway/agentgateway to 0.12.0Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/agentgateway/agentgatewayHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-29791, inspect your project dependencies for Github.com/agentgateway/agentgateway:
inspect dependencies for github.com/agentgateway/agentgatewayAnalyze the terminal output to locate any version of Github.com/agentgateway/agentgateway in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.12.0), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-20: Improper Input Validation, where the product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. In Github.com/agentgateway/agentgateway, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-29791 Affected Github.com/agentgateway/agentgateway Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/agentgateway/agentgateway
|
Go |
< 0.12.0
|
0.12.0
|
References
Frequently Asked Questions
What is CVE-2026-29791?
Which Github.com/agentgateway/agentgateway versions are affected?
What version fixes CVE-2026-29791?
Is github.com/agentgateway/agentgateway affected?
What is the CVSS score of CVE-2026-29791?
What CWE is associated with CVE-2026-29791?
How can I check Go dependencies for CVE-2026-29791?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-v2x6-wwfw-r2rq",
"modified" : "2026-03-06T22:51:46Z",
"published" : "2026-03-05T01:02:47Z",
"aliases" : [ "CVE-2026-29791" ],
"summary" : "Agentgateway is 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!",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/agentgateway/agentgateway"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.12.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"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"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-20" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-03-05T01:02:47Z",
"nvd_published_at" : "2026-03-06T21:16:15Z"
}
}