| Package | Affected versions | Patched versions |
|---|---|---|
| nuxt | ≥ 3.21.7, < 3.21.10≥ 4.4.7, < 4.5.1 | 3.21.104.5.1 |
Nuxt matches route rules case-insensitively by default (mirroring vue-router's default sensitive: false routing). The fix for GHSA-mm7m-92g8-7m47 / CVE-2026-53721 lowercased the lookup path before matching route rules, but the route-rule keys compiled into the matcher were left verbatim. As a result, any route rule whose key contains an uppercase character (for example /Admin, /Dashboard/**, or the rules Nuxt derives from PascalCase/camelCase page files such as pages/Admin.vue) never matches, because every lookup is folded to lowercase while the key stays mixed-case.
vue-router still serves the page case-insensitively, so the page renders with none of its Nuxt route-rule protections applied. The most serious consequence is an authorization bypass: an appMiddleware rule used as an auth gate (routeRules: { '/Admin/dashboard': { appMiddleware: 'auth' } }) is dropped, and /Admin/dashboard, /admin/dashboard, and /ADMIN/dashboard all render the protected page (and its SSR-fetched data) to an unauthenticated visitor instead of redirecting to login. The same gap drops Nuxt's other app-side route-rule behaviours for mixed-case keys, including the client redirect middleware, the app-side ssr: false decision, prerender, and payload handling.
Fixed in [email protected] (4.x) and [email protected] (3.x). The route-rule matcher now case-folds the compiled keys the same way it folds the lookup path, so key and lookup normalisation are symmetric. Both sides are gated on router.options.sensitive: with sensitive: true (case-sensitive routing) configured casing is preserved on both sides.
Scope note: server-emitted per-route headers, server redirect, and proxy are matched by Nitro's own case-sensitive route-rule matcher, not by Nuxt's app-level matcher. They are unchanged by this advisory. The fix covers the app-level protections Nuxt owns (appMiddleware, appLayout, the client redirect middleware, the app ssr decision, prerender, and payload).
If you cannot upgrade immediately, any one of:
routeRules (and name your page files) in lowercase, so the keys already match the folded lookup path.router: { options: { sensitive: true } } so routing and route-rule matching are both case-sensitive and exact (requests must then use the exact casing).Running one of these products? Scan your site to see whether it exposes a vulnerable version.
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