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Pin dependency esbuild to 0.24.2 [SECURITY] - #3034

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This PR contains the following updates:

Package Type Update Change
esbuild devDependencies pin ^0.24.0 → 0.24.2

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esbuild enables any website to send any requests to the development server and read the response

GHSA-67mh-4wv8-2f99

More information

Details

Summary

esbuild allows any websites to send any request to the development server and read the response due to default CORS settings.

Details

esbuild sets Access-Control-Allow-Origin: * header to all requests, including the SSE connection, which allows any websites to send any request to the development server and read the response.

https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L121
https://github.com/evanw/esbuild/blob/df815ac27b84f8b34374c9182a93c94718f8a630/pkg/api/serve_other.go#L363

Attack scenario:

  1. The attacker serves a malicious web page (http://malicious.example.com).
  2. The user accesses the malicious web page.
  3. The attacker sends a fetch('http://127.0.0.1:8000/main.js') request by JS in that malicious web page. This request is normally blocked by same-origin policy, but that's not the case for the reasons above.
  4. The attacker gets the content of http://127.0.0.1:8000/main.js.

In this scenario, I assumed that the attacker knows the URL of the bundle output file name. But the attacker can also get that information by

  • Fetching /index.html: normally you have a script tag here
  • Fetching /assets: it's common to have a assets directory when you have JS files and CSS files in a different directory and the directory listing feature tells the attacker the list of files
  • Connecting /esbuild SSE endpoint: the SSE endpoint sends the URL path of the changed files when the file is changed (new EventSource('/esbuild').addEventListener('change', e => console.log(e.type, e.data)))
  • Fetching URLs in the known file: once the attacker knows one file, the attacker can know the URLs imported from that file

The scenario above fetches the compiled content, but if the victim has the source map option enabled, the attacker can also get the non-compiled content by fetching the source map file.

PoC
  1. Download reproduction.zip
  2. Extract it and move to that directory
  3. Run npm i
  4. Run npm run watch
  5. Run fetch('http://127.0.0.1:8000/app.js').then(r => r.text()).then(content => console.log(content)) in a different website's dev tools.

image

Impact

Users using the serve feature may get the source code stolen by malicious websites.

Severity

  • CVSS Score: 5.3 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

References

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

Add the preset :preserveSemverRanges to your config if you don't want to pin your dependencies.


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This PR has been generated by Mend Renovate CLI.

@pulumi-renovate pulumi-renovate Bot added dependencies Pull requests that update a dependency file impact/no-changelog-required This issue doesn't require a CHANGELOG update labels Sep 18, 2026
@pulumi-renovate
pulumi-renovate Bot enabled auto-merge (squash) September 18, 2026 19:22
@pulumi-renovate
pulumi-renovate Bot merged commit c4ce316 into master Sep 18, 2026
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@pulumi-renovate
pulumi-renovate Bot deleted the renovate/security branch September 18, 2026 19:22
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