Nuxt is an open-source web development framework for Vue.js. From versions 3.4.3 to before 3.21.6 and 4.0.0-alpha.1 to before 4.4.6,…
GitHub_M·CWE-83·Published 2026-05-19
Nuxt is an open-source web development framework for Vue.js. From versions 3.4.3 to before 3.21.6 and 4.0.0-alpha.1 to before 4.4.6, navigateTo() with external: true generates a server-side HTML redirect body containing a <meta http-equiv="refresh"> tag. The destination URL is only sanitized by replacing " with %22, leaving <, >, &, and ' unencoded. An attacker who can influence the URL passed to navigateTo(url, { external: true }) can break out of the content="…" attribute and inject arbitrary HTML/JavaScript that executes under the application's origin. This issue has been patched in versions 3.21.6 and 4.4.6.
Nuxt is an open-source web development framework for Vue.js. From versions 3.4.3 to before 3.21.6 and 4.0.0-alpha.1 to before 4.4.6, navigateTo() with external: true generates a server-side HTML redirect body containing a <meta http-equiv="refresh"> tag. The destination URL is only sanitized by replacing " with %22, leaving <, >, &, and ' unencoded. An attacker who can influence the URL passed to navigateTo(url, { external: true }) can break out of the content="…" attribute and inject arbitrary HTML/JavaScript that executes under the application's origin. This issue has been patched in versions 3.21.6 and 4.4.6.
### Summary `navigateTo()` with `external: true` generates a server-side HTML redirect body containing a `<meta http-equiv="refresh">` tag. The destination URL is only sanitized by replacing `"` with `%22`, leaving `<`, `>`, `&`, and `'` unencoded. An attacker who can influence the URL passed to `navigateTo(url, { external: true })` can break out of the `content="…"` attribute and inject arbitrary HTML/JavaScript that executes under the application's origin. This is a different root cause from CVE-2024-34343 (GHSA-vf6r-87q4-2vjf), which addressed `javascript:` protocol bypass. The issue here is triggered by any valid URL containing `>`. ### Impact Applications that pass user-controlled input to `navigateTo(url, { external: true })` — typically via a `?next=` / `?redirect=` query parameter used for post-login or "return to" flows — are vulnerable to reflected cross-site scripting. The injected script runs in the context of the application's origin during the server-rendered redirect response, before the meta-refresh fires. ### Details In `packages/nuxt/src/app/composables/router.ts`, the SSR redirect path builds an HTML response body with only `"` percent-encoded in the destination URL: ```ts const encodedLoc = location.replace(/"/g, '%22') nuxtApp.ssrContext!['~renderResponse'] = { status: sanitizeStatusCode(options?.redirectCode || 302, 302), body: `<!DOCTYPE html><html><head><meta http-equiv="refresh" content="0; url=${encodedLoc}"></head></html>`, headers: { location: encodeURL(location, isExternalHost) }, } ``` The `Location` header is normalised through `encodeURL()` (which uses the `URL` constructor and correctly percent-encodes attribute-significant characters). The HTML body uses a narrower sanitiser. That mismatch is the root cause. ### Proof of concept Global middleware that forwards a query parameter to `navigateTo`: ```ts // middleware/redirect.global.ts export default defineNuxtRouteMiddleware((to) => { const next = to.query.next as string | undefined if (next) { return navigateTo(next, { external: true }) } }) ``` Request: ``` GET /?next=https://evil.example/x><img src=x onerror=alert(document.domain)> ``` Response body: ```html <!DOCTYPE html><html><head><meta http-equiv="refresh" content="0; url=https://evil.example/x><img src=x onerror=alert(document.domain)>"></head></html> ``` The `>` after `evil.example/x` terminates the `content="…"` attribute, and the `<img onerror>` tag executes JavaScript in the application's origin before any redirect occurs. ### Patches Fixed in `nuxt@4.4.6` and `nuxt@3.21.6` by [#35052](https://github.com/nuxt/nuxt/pull/35052). The fix percent-encodes the full set of HTML-attribute-significant characters (`&`, `"`, `'`, `<`, `>`) before interpolating the URL into the meta-refresh body ### Workarounds If you can't upgrade immediately, validate user-controlled URLs before passing them to `navigateTo(url, { external: true })`. At minimum, normalise through `new URL(input).toString()` and reject inputs containing `<` or `>` (a normalised URL with these characters is malformed and safe to refuse).
### Summary `navigateTo()` with `external: true` generates a server-side HTML redirect body containing a `<meta http-equiv="refresh">` tag. The destination URL is only sanitized by replacing `"` with `%22`, leaving `<`, `>`, `&`, and `'` unencoded. An attacker who can influence the URL passed to `navigateTo(url, { external: true })` can break out of the `content="…"` attribute and inject arbitrary HTML/JavaScript that executes under the application's origin. This is a different root cause from CVE-2024-34343 (GHSA-vf6r-87q4-2vjf), which addressed `javascript:` protocol bypass. The issue here is triggered by any valid URL containing `>`. ### Impact Applications that pass user-controlled input to `navigateTo(url, { external: true })` — typically via a `?next=` / `?redirect=` query parameter used for post-login or "return to" flows — are vulnerable to reflected cross-site scripting. The injected script runs in the context of the application's origin during the server-rendered redirect response, before the meta-refresh fires. ### Details In `packages/nuxt/src/app/composables/router.ts`, the SSR redirect path builds an HTML response body with only `"` percent-encoded in the destination URL: ```ts const encodedLoc = location.replace(/"/g, '%22') nuxtApp.ssrContext!['~renderResponse'] = { status: sanitizeStatusCode(options?.redirectCode || 302, 302), body: `<!DOCTYPE html><html><head><meta http-equiv="refresh" content="0; url=${encodedLoc}"></head></html>`, headers: { location: encodeURL(location, isExternalHost) }, } ``` The `Location` header is normalised through `encodeURL()` (which uses the `URL` constructor and correctly percent-encodes attribute-significant characters). The HTML body uses a narrower sanitiser. That mismatch is the root cause. ### Proof of concept Global middleware that forwards a query parameter to `navigateTo`: ```ts // middleware/redirect.global.ts export default defineNuxtRouteMiddleware((to) => { const next = to.query.next as string | undefined if (next) { return navigateTo(next, { external: true }) } }) ``` Request: ``` GET /?next=https://evil.example/x><img src=x onerror=alert(document.domain)> ``` Response body: ```html <!DOCTYPE html><html><head><meta http-equiv="refresh" content="0; url=https://evil.example/x><img src=x onerror=alert(document.domain)>"></head></html> ``` The `>` after `evil.example/x` terminates the `content="…"` attribute, and the `<img onerror>` tag executes JavaScript in the application's origin before any redirect occurs. ### Patches Fixed in `nuxt@4.4.6` and `nuxt@3.21.6` by [#35052](https://github.com/nuxt/nuxt/pull/35052). The fix percent-encodes the full set of HTML-attribute-significant characters (`&`, `"`, `'`, `<`, `>`) before interpolating the URL into the meta-refresh body ### Workarounds If you can't upgrade immediately, validate user-controlled URLs before passing them to `navigateTo(url, { external: true })`. At minimum, normalise through `new URL(input).toString()` and reject inputs containing `<` or `>` (a normalised URL with these characters is malformed and safe to refuse).
| Version | Type | Source | Base | Exp | Impact | Vector |
|---|---|---|---|---|---|---|
| 3.1 | Primary | NVD | 5.4 | 2.8 | 2.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N |
| 4.0 | Primary | cve.org | 5.3 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N |
| 4.0 | Primary | cve.org | 5.3 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N |
| 4.0 | Secondary | NVD | 5.3 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| 4.0 | Secondary | ENISA EUVD | 5.3 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N |
| 4.0 | Secondary | GHSA | 5.3 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N |