GHSA-6gq8-jgmh-3ffp - Nuxt: Route rules are matched against the raw request path, so a percent-encoded segment can bypass `appMiddleware` on dynamic and catch-all routes
### Summary
Nuxt compared `routeRules` keys against the raw request path, without decoding percent-encoding, while the router decodes parameters when it resolves a route. A request whose path is percent-encoded can therefore resolve to a page while failing to match the route rule meant to protect it, so the rule's `appMiddleware` never runs, including during server rendering.
### Impact
For a page served through a dynamic or catch-all route, an attacker can percent-encode a character in the path to skip the rule:
```ts
export default defineNuxtConfig({
routeRules: {
'/users/admin': { appMiddleware: 'auth' },
},
})
```
Requesting `/users/%61dmin` still renders `app/pages/users/[id].vue` with `id` decoded to `admin`, but the rule keyed `/users/admin` does not match, so `auth` does not run and the server renders and returns the gated page to an unauthenticated visitor. No privileges and no user interaction are required, and only ASCII characters are involved.
Purely static ASCII routes are not affected: static segments are matched without decoding, so a request for `/%61dmin` does not resolve to the page registered at `/admin` and 404s instead of rendering.
The rule keys affected are the ones carried in the app manifest and consumed by the app: `appMiddleware`, `redirect`, `appLayout`, `ssr`, `prerender`, and the payload flags derived from `cache`, `isr` and `swr`.
If you have pinned or overridden dependency versions below what your Nuxt release declares, a release outside the affected ranges can still be exposed, so do not conclude from a single reproduction that you are unaffected.
### Patches
Releases from `4.4.4` and `3.21.4` are not affected, because their dependency floor requires a version of the underlying HTTP layer that normalises percent-encoding in the request path before routing, which removes the mismatch in a default install.
The comparison itself is fixed in `nuxt@4.5.2` and `nuxt@3.21.11`: route-rule keys and lookup paths are now dec
MEDIUM
Severity & confidence
Source severitymedium
Platform severitymedium
Confidencehigh
Exploitationunknown
CVSS6.5
Affected
Vendorsnuxt
Productsnuxt
Reporting sources (2)
GitHub Security Advisories
NIST NVD - National Vulnerability Database
Timeline & provenance
Published2026-10-22T16:50:53
Last updated2026-10-25T02:26:18
Ingested2026-10-22T16:54:35
FreshnessNEAR-REAL-TIME
Threat typeadvisory
Recommended action
Review the advisory and upgrade affected packages to the first patched version.
Next steps
- Identify affected systems in your environment.
- Apply the vendor patch or mitigation guidance.
- Review logs for indicators described in the advisory.
- Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: vendor ยท Original: GitHub Security Advisories