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fix(deps): update dependency astro to v7.1.0 [security]#340

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fix(deps): update dependency astro to v7.1.0 [security]#340
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renovate/npm-astro-vulnerability

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This PR contains the following updates:

Package Change Age Confidence
astro (source) 7.0.97.1.0 age confidence

Astro: Reflected XSS via unescaped View Transition animation properties

GHSA-4g3v-8h47-v7g6

More information

Details

Summary

Astro's server-side View Transition CSS generator interpolates animation properties into an inline <style> element without escaping them for the CSS and HTML contexts.

An attacker-controlled value passed to an animation property such as duration can contain a </style> sequence, terminate the generated style element, and inject arbitrary HTML or JavaScript.

This is similar to GHSA-8hv8-536x-4wqp, but exploits a different injection point: unescaped View Transition animation values in a server-generated <style> element rather than an unescaped slot name in a hydration template.

Like GHSA-8hv8-536x-4wqp, exploitation requires an application to pass attacker-controlled data to an Astro API. However, the value is subsequently inserted into the HTML response without context-appropriate escaping by Astro.

Details

packages/astro/src/runtime/server/transition.ts

The generated stylesheet is wrapped in a <style> element and marked as HTML-safe:

const css = sheet.toString();
result._metadata.extraHead.push(markHTMLString(`<style>${css}</style>`));

Animation properties are added to the stylesheet without escaping:

if (anim.duration) {
  addAnimationProperty(builder, 'animation-duration', toTimeValue(anim.duration));
}

For string values, toTimeValue() returns the input unchanged:

export function toTimeValue(num: number | string) {
  return typeof num === 'number' ? num + 'ms' : num;
}

As a result, a duration value containing </style> can escape from the generated style element.

Other TransitionAnimation properties, including easing, direction, delay, fillMode, and name, are serialized by the same animation builder. The following PoC only relies on the official fade() helper and its duration option.

PoC

Using:

  • astro@7.0.9
  • @astrojs/node@11.0.2
astro.config.mjs
import node from '@&#8203;astrojs/node';
import { defineConfig } from 'astro/config';

export default defineConfig({
  output: 'server',
  adapter: node({ mode: 'standalone' }),
});
src/pages/index.astro
---
import { fade } from 'astro:transitions';

const duration = Astro.url.searchParams.get('duration') ?? '300ms';
---

<html lang="en">
  <head>
    <meta charset="utf-8" />
    <title>PoC</title>
  </head>
  <body>
    <div transition:animate={fade({ duration })}>
      Animated content
    </div>
  </body>
</html>
Payload:

open:

http://localhost:4321/?duration=%3C%2Fstyle%3E%3Cscript%3Ealert(1)%3C%2Fscript%3E%3C!--

The browser interprets </style> as the end of the generated style element and executes the injected script. An alert dialog is displayed when the page is opened.

image
Impact

An attacker who can control a View Transition animation value can execute arbitrary JavaScript in the origin of the affected Astro application.

The query-based reflected XSS scenario affects on-demand/server-rendered routes, such as:

  • projects configured with output: "server";
  • pages using export const prerender = false;
  • other server-side data flows that pass attacker-controlled values into a View Transition animation definition.

Successful exploitation may allow access to sensitive page data and authenticated actions available to the victim.

Suggested Fix

Animation values should be serialized using context-appropriate CSS escaping or validation before being added to the generated stylesheet.

Additionally, content inserted into a raw <style> element must not be able to contain an HTML end-tag sequence such as </style>. The final generated CSS should be made safe for the HTML raw-text context before it is passed to markHTMLString().

Severity

  • CVSS Score: 5.3 / 10 (Medium)
  • Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References

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


Release Notes

withastro/astro (astro)

v7.1.0

Compare Source

Minor Changes
  • #​17302 5f4dc03 Thanks @​astrobot-houston! - Adds a new deferRender option to the glob() content loader

    When set to true, renderable entries (such as Markdown) are not rendered during content sync. Instead, rendering is deferred until the entry is actually rendered in a page, using the same on-demand path that .mdx files already use.

    This reduces memory usage during astro build for large collections whose rendered output is much larger than the source — for example, Markdown that uses heavy rehype plugins like rehype-katex. Such builds could previously run out of memory while storing the eagerly-rendered HTML for every entry.

    // src/content.config.ts
    import { defineCollection } from 'astro:content';
    import { glob } from 'astro/loaders';
    
    const docs = defineCollection({
      loader: glob({ pattern: '**/*.md', base: 'src/content/docs', deferRender: true }),
    });

    By default deferRender is false, preserving the existing behavior of rendering entries eagerly during sync so their rendered HTML can be cached across builds.

  • #​17296 30698a2 Thanks @​ematipico! - Adds a new experimental collectionStorage option for controlling how the content layer persists its data store

    By default, Astro serializes the entire content layer data store to a single file (.astro/data-store.json). For very large content collections, this file can grow large enough to hit platform file-size limits.

    Set experimental.collectionStorage: 'chunked' to instead split the data store across many smaller, content-addressed files inside a .astro/data-store/ directory, described by a manifest:

    // astro.config.mjs
    import { defineConfig } from 'astro/config';
    
    export default defineConfig({
      experimental: {
        collectionStorage: 'chunked',
      },
    });

    Because each part file is named by a hash of its contents, unchanged parts keep the same name across builds and are not rewritten, and identical parts are deduplicated. The default value is 'single-file', which preserves the current behavior.

  • #​17214 44c4989 Thanks @​ematipico! - Adds support for the more specific CSP directives script-src-elem, script-src-attr, style-src-elem, and style-src-attr through a new kind option.

    Previously, CSP was only scoped to generic script-src/style-src directives. Now each source or hash can be scoped to a narrower directive — for example, to allow inline style attributes (such as those from define:vars or Shiki) without loosening the policy for your <style> and <link> elements.

Scoping sources and hashes in your config

Each entry in resources and hashes can be an object with a kind property. Depending on whether you use scriptDirective or styleDirective, "element" targets script-src-elem or style-src-elem, "attribute" targets script-src-attr or style-src-attr, and "default" (the same as a bare string or hash) targets script-src or style-src.

// astro.config.mjs
import { defineConfig } from 'astro/config';

export default defineConfig({
  security: {
    csp: {
      scriptDirective: {
        resources: [{ resource: 'https://cdn.example.com', kind: 'element' }],
      },
      styleDirective: {
        resources: [{ resource: "'unsafe-inline'", kind: 'attribute' }],
      },
    },
  },
});
Scoping at runtime

The same kind option is available on the runtime CSP API, where the existing methods now also accept an object:

ctx.csp.insertScriptResource({ resource: 'https://cdn.example.com', kind: 'element' });
ctx.csp.insertStyleResource({ resource: "'unsafe-inline'", kind: 'attribute' });
  • #​17258 84814d4 Thanks @​astrobot-houston! - Adds a new format() option to the paginate utility. The format() option is a function that accepts the current URL of the page, and returns a new URL.

    For example, when your host only supports URLs using the .html extension, you can use format() to add it to the generated URLs:

    ---
    export async function getStaticPaths({ paginate }) {
      // Load your data with fetch(), getCollection(), etc.
      const response = await fetch(`https://pokeapi.co/api/v2/pokemon?limit=150`);
      const result = await response.json();
      const allPokemon = result.results;
    
      // Return a paginated collection of paths for all items
      return paginate(allPokemon, {
        pageSize: 10,
        format: (url) => `${url}.html`,
      });
    }
    
    const { page } = Astro.props;
    ---
  • #​17331 7db6420 Thanks @​matthewp! - Adds a --ignore-lock flag to astro dev for starting a dev server without checking or writing the lock file, so it can run alongside an already-running dev server for the same project.

    The new instance is not tracked by astro dev stop, astro dev status, or astro dev logs. --ignore-lock cannot be combined with --background (or an auto-detected AI agent environment, which runs dev servers in the background automatically) or --force, since those rely on the lock file.

    astro dev --ignore-lock
  • #​17389 16de021 Thanks @​florian-lefebvre! - Allows passing URL entrypoints when configuring the logger

    Matching other APIs like session drivers or font providers, the logger entrypoint can now be a URL:

    import { defineConfig } from 'astro/config';
    
    export default defineConfig({
      logger: {
        entrypoint: new URL('./logger.js', import.meta.url),
      },
    });
Patch Changes
  • #​17332 4407483 Thanks @​astrobot-houston! - Fixes the JSON logger crashing with process is not defined in non-Node runtimes like Cloudflare's workerd. The JSON logger now uses console.log/console.error instead of process.stdout/process.stderr, matching the pattern already used by the console logger.

  • #​17391 186a1e7 Thanks @​florian-lefebvre! - Fixes a case where an integration could not update the logger with updateConfig()

  • #​17394 d9f99e1 Thanks @​matthewp! - Fixes element-specific CSP directives to preserve the existing behavior of configured script and style resources

  • #​17374 b2d1b3e Thanks @​astrobot-houston! - Fixes dev server returning 404 for ?url imported assets when accessed via browser navigation

  • #​17390 ed71eaf Thanks @​florian-lefebvre! - Removes an unused and undocumented generic from the AstroLoggerDestination type

  • #​17393 092da56 Thanks @​matthewp! - Hardens generated transition styles, development metadata, and server island URLs when embedding dynamic values


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This PR was generated by Mend Renovate. View the repository job log.

@renovate renovate Bot added the dependencies Pull requests that update a dependency file label Jul 21, 2026
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renovate Bot requested a review from anconina as a code owner July 21, 2026 10:09
@renovate renovate Bot added the dependencies Pull requests that update a dependency file label Jul 21, 2026
@socket-security

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Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff Package Supply Chain
Security
Vulnerability Quality Maintenance License
Updatedastro@​7.0.9 ⏵ 7.1.088100 +288 +198100

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@socket-security

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Warning

Review the following alerts detected in dependencies.

According to your organization's Security Policy, it is recommended to resolve "Warn" alerts. Learn more about Socket for GitHub.

Action Severity Alert  (click "▶" to expand/collapse)
Warn High
Obfuscated code: npm astro is 90.0% likely obfuscated

Confidence: 0.90

Location: Package overview

From: website/package-lock.jsonnpm/astro@7.1.0

ℹ Read more on: This package | This alert | What is obfuscated code?

Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at support@socket.dev.

Suggestion: Packages should not obfuscate their code. Consider not using packages with obfuscated code.

Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment @SocketSecurity ignore npm/astro@7.1.0. You can also ignore all packages with @SocketSecurity ignore-all. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.

View full report

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