GHSA-jpvv-r467-5p4w

Source

https://github.com/advisories/GHSA-jpvv-r467-5p4w

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/11/GHSA-jpvv-r467-5p4w/GHSA-jpvv-r467-5p4w.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-jpvv-r467-5p4w

Aliases

CVE-2026-126210

Published

2026-11-12T21:28:02Z

Modified

2026-11-12T21:45:03Z

Severity

5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator

Summary

@hono/node-server: Backslash in the request path is parsed as a path separator, bypassing path-based access control at a reverse proxy

Details

Summary

@hono/node-server passes the raw request-target to the WHATWG URL parser, which treats a backslash in the path as / and then resolves .. segments. A request for /admin\secret or /public\..\admin/secret reaches the application as /admin/secret. A reverse proxy that follows RFC 3986 forwards the backslash unchanged and applies its path-based rules to the original path, so the request reaches a route the proxy is meant to block.

Details

A raw backslash is not allowed in a request-target (RFC 3986, RFC 9112 Section 3.2.1), and RFC 9112 Section 3.2 says a recipient should reject such a request rather than correct it. Proxies such as nginx on Linux, HAProxy and Envoy keep the backslash as an ordinary character, so they and the application see different paths.

The fix responds with 400 Bad Request to a request whose path contains a raw backslash, for HTTP/1.1, HTTP/2, absolute-form request-targets and WebSocket upgrades. A percent-encoded backslash and a backslash in the query string are still accepted.

Impact

An unauthenticated client can reach a route that a reverse proxy, load balancer or WAF in front of the application blocks by path.

This affects applications served by @hono/node-server behind a front component that makes path-based decisions and forwards a backslash unchanged. Access control inside the Hono application, such as middleware on /admin/*, runs on the rewritten path and is not affected.

Database specific

{
    "cwe_ids": [
        "CWE-436"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-11-12T21:28:02Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
}

References

Affected packages

npm / @hono/node-server

Package

Name: @hono/node-server; View open source insights on deps.dev
Purl: pkg:npm/%40hono/node-server

Affected ranges

Type: SEMVER
Events: Introduced

2.0.0

Fixed

2.1.6

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/11/GHSA-jpvv-r467-5p4w/GHSA-jpvv-r467-5p4w.json"

npm / @hono/node-server

Package

Name: @hono/node-server; View open source insights on deps.dev
Purl: pkg:npm/%40hono/node-server

Affected ranges

Type: SEMVER
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

1.19.18

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/11/GHSA-jpvv-r467-5p4w/GHSA-jpvv-r467-5p4w.json"