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chore(deps): update dependency @astrojs/vercel to v11 [security] - #388

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This PR contains the following updates:

Package Change Age Confidence
@astrojs/vercel (source) ^10.0.0 → ^11.0.0 age confidence

Astro: Unauthenticated path override in the @​astrojs/vercel ISR function

CVE-2026-73424 / GHSA-x27w-589x-frm2

More information

Details

Summary

When ISR is enabled, the serverless entrypoint lets an unauthenticated request
decide which route the origin renders. The internal _isr function reads the
x_astro_path query parameter and rewrites the request path to it without any
authentication. Edge level access controls only ever see the /_isr path, so
they do not apply to the route that actually gets rendered. This is the same
confused deputy problem as CVE-2026-33768, reachable again through the ISR path.

Impact

This affects apps that use @astrojs/vercel with isr: true and protect routes
at the edge. Two common setups are affected:

  1. Path rules or firewall deny rules configured on Vercel (for example blocking
    /admin).
  2. Split deployments (edgeMiddleware: true) where authorization lives in Astro
    middleware, since that middleware runs at the edge and not in the origin.

An attacker reads any GET rendered route by requesting
/_isr?x_astro_path=/the/protected/path. No credentials are required. The
protected content is produced by a fresh origin render, so the attack does not
depend on the response being cached first.

Details

packages/integrations/vercel/src/serverless/entrypoint.ts picks the real path
like this:

if (hasValidMiddlewareSecret) {
  realPath = request.headers.get(ASTRO_PATH_HEADER);       // secret checked
} else if (request.headers.get('x-vercel-isr') === '1') {
  realPath = url.searchParams.get(ASTRO_PATH_PARAM);        // no secret checked
}

The header path is gated by the per build secret and is fine. The ISR branch is
not. Two facts make it reachable by anyone:

  1. The _isr function is publicly addressable.
  2. Vercel sets x-vercel-isr: 1 on requests to it, including direct external
    requests, so the attacker does not even need to send that header.

So GET /_isr?x_astro_path=/admin sets the internal path to /admin and renders
it. The edge saw only /_isr, which is allowed, so any path based rule on
/admin never fires. In split deployments the edge middleware also runs against
/_isr, and the origin does not run middleware at all, so middleware based auth
is skipped as well.

How this regressed

CVE-2026-33768 was fixed in 10.0.2 by commit 335a204161 (PR #​15959), which
required the secret for every path override and removed the query parameter
source. Commit aa266364fe (PR #​16079, "Fix ISR path rewrite to prevent 404")
brought the query parameter back, guarded only by the x-vercel-isr header. That
header is not a security boundary, so the fix was effectively undone for ISR
routes starting in 10.0.3.

Worth noting the contrast: the original report treated Edge Middleware as the
mitigation and scoped the issue to deployments without it. Here, for split
deployments, Edge Middleware is bypassed too, since the attacker reaches /_isr
directly and the middleware only sees /_isr while the origin runs none.

Proof of concept
  1. Create an Astro app with output: 'server' and adapter
    vercel({ isr: true }).
  2. Add a page at /admin that returns sensitive content.
  3. Deny /admin at the edge, for example a Vercel path rule that returns 403, or
    a middleware auth check in a split (edgeMiddleware: true) build.
  4. Request /admin. It is blocked (403).
  5. Request /_isr?x_astro_path=/admin. It returns 200 with the admin content.
    The response header X-Vercel-Cache: MISS confirms it was rendered fresh, not
    served from an existing cache entry.
What is not affected
  1. Classic (non split) middleware. It runs inside the origin against the rewritten
    path, so it still applies to the target route.
  2. State changing requests. Vercel serves ISR functions for GET only, and returns
    403 for POST, PUT and DELETE, so the method preserving variant of CVE-2026-33768
    does not reproduce here. Impact is limited to reading (confidentiality).
  3. Whole deployment protection (Vercel SSO or password), which also covers /_isr.
Severity

Unauthenticated read of any GET rendered route that is protected only at the edge.
No integrity or availability impact because the vector is GET only.

Suggested fix

One option would be to require the secret again for path overrides, the way
PR #​15959 did, so the ISR branch stops trusting the client supplied x_astro_path.
The 404 that PR #​16079 was fixing would then need another approach that does not
rely on client input.

Severity

  • CVSS Score: 6.5 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).


Release Notes

withastro/astro (@​astrojs/vercel)

v11.0.3

Compare Source

Patch Changes

v11.0.2

Compare Source

Patch Changes

v11.0.1

Compare Source

Patch Changes
  • #​18339 fcc050c Thanks @​astro-factory! - Fixes on-demand routes failing with "Cannot find native binding" on Vercel, caused by the serverless function loading rolldown at runtime

v11.0.0

Compare Source

Major Changes
Minor Changes
Setup

Import cacheVercel() from @astrojs/vercel/cache and set it as your cache provider:

import { defineConfig } from 'astro/config';
import vercel from '@astrojs/vercel';
import { cacheVercel } from '@astrojs/vercel/cache';

export default defineConfig({
  adapter: vercel(),
  cache: {
    provider: cacheVercel(),
  },
});
Caching responses

Use Astro.cache.set() in your pages and API routes to cache responses on Vercel's edge network. The provider sets Vercel-CDN-Cache-Control and Vercel-Cache-Tag headers on responses.

---
Astro.cache.set({ maxAge: 300, tags: ['products'] });
const data = await fetchProducts();
---

<ProductList items={data} />

You can also set cache rules for groups of routes in your config:

cache: { provider: cacheVercel() },
routeRules: {
  '/products/[...slug]': { maxAge: 3600, tags: ['products'] },
  '/api/[...path]': { maxAge: 60, swr: 600 },
},
Invalidation

Purge cached responses by tag or path from any API route or server endpoint:

// src/pages/api/purge.ts
export async function POST({ request, cache }) {
  await cache.invalidate({ tags: ['products'] });
  return new Response('Purged');
}

// Path-based invalidation
await cache.invalidate({ path: '/products/123' });

Both tag-based and path-based invalidation are supported. Tag invalidation is a soft invalidation, marking cached responses as stale so they can be revalidated in the background via stale-while-revalidate.

Patch Changes

Configuration

📅 Schedule: (UTC)

  • Branch creation
    • At any time (no schedule defined)
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    • At any time (no schedule defined)

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

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@vercel

vercel Bot commented Aug 26, 2026 •

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The latest updates on your projects. Learn more about Vercel for GitHub.

Project Deployment Actions Updated
code-snippets Error Error Oct 13, 2026 11:57am UTC

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changeset-bot Bot commented Aug 26, 2026 •

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⚠️ No Changeset found

Latest commit: d4b2cea

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@renovate
renovate Bot force-pushed the renovate/npm-astrojs-vercel-vulnerability branch from 5a642a5 to 9a5d0ea Compare September 2, 2026 19:16
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renovate Bot force-pushed the renovate/npm-astrojs-vercel-vulnerability branch from 9a5d0ea to 1561539 Compare September 3, 2026 18:53
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renovate Bot force-pushed the renovate/npm-astrojs-vercel-vulnerability branch from 1561539 to b581614 Compare September 15, 2026 20:28
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renovate Bot force-pushed the renovate/npm-astrojs-vercel-vulnerability branch from b581614 to cc33d72 Compare September 23, 2026 03:10
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renovate Bot force-pushed the renovate/npm-astrojs-vercel-vulnerability branch from cc33d72 to 0bea82f Compare September 25, 2026 03:56
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renovate Bot force-pushed the renovate/npm-astrojs-vercel-vulnerability branch from 0bea82f to 0e3aabc Compare October 5, 2026 19:03
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renovate Bot force-pushed the renovate/npm-astrojs-vercel-vulnerability branch from 0e3aabc to d4b2cea Compare October 13, 2026 11:57

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