Nuxt: Route rules are matched against the raw request path, so a percent-encoded segment can bypass `appMiddleware` on dynamic and catch-all routes

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Nuxt is an open-source web development framework for Vue.js. From 3.11.0 until 3.21.4 and 4.4.4, Nuxt compares route-rule keys with the raw request path while route resolution decodes dynamic and catch-all parameters, allowing a percent-encoded segment to resolve to a protected page without matching the routeRules entry intended for that path. As a result, appMiddleware can be skipped during server rendering and an unauthenticated requester can receive the gated page and its SSR data. The same mismatch affects app-manifest rules including redirect, appLayout, ssr, prerender, and payload flags derived from cache, isr, and swr. This vulnerability is fixed in 4.4.4 and 3.21.4.

Source published

21 Oct 2026 17:41:24 UTC

Source modified

30 Oct 2026 17:48:52 UTC

Observed here

30 Oct 2026 18:45:26 UTC

Source terms

CVE Program Terms of Use

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CVSS 3.1 · 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Nuxt is an open-source web development framework for Vue.js. From 3.11.0 until 3.21.4 and 4.4.4, Nuxt compares route-rule keys with the raw request path while route resolution decodes dynamic and catch-all parameters, allowing a percent-encoded segment to resolve to a protected page without matching the routeRules entry intended for that path. As a result, appMiddleware can be skipped during server rendering and an unauthenticated requester can receive the gated page and its SSR data. The same mismatch affects app-manifest rules including redirect, appLayout, ssr, prerender, and payload flags derived from cache, isr, and swr. This vulnerability is fixed in 4.4.4 and 3.21.4.

Source published

Oct 21, 2026, 5:41:24 PM (timezone not stated)

Source modified

Oct 30, 2026, 5:48:52 PM (timezone not stated)

Observed here

7 Nov 2026 04:35:50 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Nuxt is an open-source web development framework for Vue.js. From 3.11.0 until 3.21.4 and 4.4.4, Nuxt compares route-rule keys with the raw request path while route resolution decodes dynamic and catch-all parameters, allowing a percent-encoded segment to resolve to a protected page without matching the routeRules entry intended for that path. As a result, appMiddleware can be skipped during server rendering and an unauthenticated requester can receive the gated page and its SSR data. The same mismatch affects app-manifest rules including redirect, appLayout, ssr, prerender, and payload flags derived from cache, isr, and swr. This vulnerability is fixed in 4.4.4 and 3.21.4.

Source published

21 Oct 2026 18:17:25 UTC

Source modified

30 Oct 2026 18:17:22 UTC

Observed here

31 Oct 2026 06:57:45 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

### 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 `[email protected]` and `[email protected]`: route-rule keys and lookup paths are now decoded (and, unless `router.options.sensitive` is set, case-folded) before they are compared. Reserved escapes such as `%2F` are left encoded, so decoding cannot introduce extra path segments, and paths that cannot be decoded are matched verbatim. Upgrading to those releases is recommended, since it fixes the comparison rather than relying on a dependency to normalise the input, and it also restores route rules for pages whose paths contain non-ASCII characters. ### Workarounds If you cannot upgrade, do not rely on a `routeRules` key alone to protect a route. Attach the middleware to the page itself, which binds it to the resolved route rather than to the raw path string: ```vue <script setup lang="ts"> definePageMeta({ middleware: 'auth' }) </script> ``` ### Credits Thanks to @sushi-gif, whose report that route rules keyed with non-ASCII paths never match the routes generated for those pages prompted the review that found this issue.

Source published

22 Oct 2026 16:50:53 UTC

Source modified

22 Oct 2026 17:00:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Publisher rating · MODERATE