CVE-2026-39406: @hono/node-server Middleware Bypass Vulnerability
MODERATECVE-2026-39406 is a MODERATE (CVSS 5.3) middleware bypass vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting @hono/node-server libraries in the npm ecosystem. The issue involves middleware bypass via repeated slashes in servestatic. Remediation is available by upgrading affected packages to version 1.19.13.
CVE-2026-39406 at a Glance
Security Impact
CVSS: 5.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N).
How to Fix CVE-2026-39406
To remediate this vulnerability, upgrade all affected @hono/node-server dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
npm install @hono/node-server@1.19.13Run the following command in your project directory to verify that all resolved dependencies use the patched release:
npm ls @hono/node-serverHow to Check if You Are Affected
To determine whether your Node.js application is affected by CVE-2026-39406, inspect your project dependencies using npm:
npm ls @hono/node-serverAnalyze the terminal output to locate any version of @hono/node-server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.19.13), your application is affected.
Note: The npm ls @hono/node-server command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In @hono/node-server, 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-2026-39406 Affected @hono/node-server Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
@hono/node-server
|
npm |
< 1.19.13
|
1.19.13
|
References
Frequently Asked Questions
What is CVE-2026-39406?
Which @hono/node-server versions are affected?
What version fixes CVE-2026-39406?
Is @hono/node-server affected?
What is the CVSS score of CVE-2026-39406?
What CWE is associated with CVE-2026-39406?
How can I check npm dependencies for CVE-2026-39406?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-92pp-h63x-v22m",
"modified" : "2026-04-08T15:34:25Z",
"published" : "2026-04-08T00:16:39Z",
"aliases" : [ "CVE-2026-39406" ],
"summary" : "@hono/node-server: Middleware bypass via repeated slashes in serveStatic",
"details" : "## Summary\n\nA path handling inconsistency in `serveStatic` allows protected static files to be accessed by using repeated slashes (`//`) in the request path.\n\nWhen route-based middleware (e.g., `/admin/*`) is used for authorization, the router may not match paths containing repeated slashes, while `serveStatic` resolves them as normalized paths. This can lead to a middleware bypass.\n\n## Details\n\nThe routing layer and `serveStatic` handle repeated slashes differently.\n\nFor example:\n\n- `/admin/secret.txt` => matches `/admin/*`\n- `//admin/secret.txt` => may not match `/admin/*`\n\nThis inconsistency allows a request such as:\n\n```\nGET //admin/secret.txt\n```\n\nto bypass middleware registered on `/admin/*` and access protected files.\n\n## Impact\n\nAn attacker can access static files that are intended to be protected by route-based middleware by using repeated slashes in the request path.\n\nThis can lead to unauthorized access to sensitive files under the static root.\n\nThis issue affects applications that rely on `serveStatic` together with route-based middleware for access control.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "npm",
"name" : "@hono/node-server"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "1.19.13"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/honojs/node-server/security/advisories/GHSA-92pp-h63x-v22m"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39406"
}, {
"type" : "WEB",
"url" : "https://github.com/honojs/node-server/commit/025c30f55d589ddbe6048b151d77e904f67a8cc2"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/honojs/node-server"
}, {
"type" : "WEB",
"url" : "https://github.com/honojs/node-server/releases/tag/v1.19.13"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-22" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-04-08T00:16:39Z",
"nvd_published_at" : "2026-04-08T15:16:14Z"
}
}