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@timneutkens timneutkens released this 22 Jan 19:16
· 19250 commits to canary since this release
4.2.3
44de0f1

Release notes

This upgrade is completely backwards compatible and recommended for all users
For future security related communications of our OSS projects, please join this mailing list.

We were notified of a directory traversal issue under the /_next request namespace.
An attacker can craft a request that accesses potentially sensitive information in your filesystem.

How to upgrade

  • We have released patch versions of the stable and beta releases.
  • The following versions fix this bug and include precautions to avoid
    similar problems in the future
  • Run npm install next@latest --save
  • When using canary release channel use npm install next@canary --save

Impact

  • Affected: Users of Next.js prior to this release
  • Not affected: Deployments on https://now.sh (like https://zeit.co) are mitigated. A platform wide mitigation was implemented immediately after the report was received.
  • Not affected: Static deployments via next export

We recommend everyone to upgrade regardless of whether you can reproduce the issue or not.

Container-based deployments, chroot environments and virtualization users are at significantly less risk of sensitive data exposure. In most scenarios, an attacker would only be able to access frontend JavaScript components exclusively.

How to assess impact

If you think sensitive code or data could have been exposed, please filter logs of affected sites by .. (excluding quotes in all cases) and check for 200 responses.

What is being done

As Next.js has grown in popularity, it has received the attention of security researchers and auditors. We are thankful to Orange Tsai from DEVCORE for his investigation and discovery of the original bug and subsequent responsible disclosure.

6 months ago there was a similar, but different, path traversal possible on paths under the /static directory. To prevent future regressions regarding path traversal we have separated all security related tests to a common file called security.js so that any future commit will be verified against these known fixed vulnerabilities.

  • We have notified known Next.js users in advance of this publication.
  • A public CVE was released
  • If you want to stay on top of our security related news impacting Next.js or other projects, please join this mailing list.
  • We encourage responsible disclosure of future issues. Please email us at security@zeit.co. We are actively monitoring this mailbox.
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