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Next.js Server-Side Request Forgery in Server Actions

High severity GitHub Reviewed Published May 9, 2024 in vercel/next.js • Updated May 14, 2024

Package

npm next (npm)

Affected versions

>= 13.4.0, < 14.1.1

Patched versions

14.1.1

Description

Impact

A Server-Side Request Forgery (SSRF) vulnerability was identified in Next.js Server Actions by security researchers at Assetnote. If the Host header is modified, and the below conditions are also met, an attacker may be able to make requests that appear to be originating from the Next.js application server itself.

Prerequisites

  • Next.js (<14.1.1) is running in a self-hosted* manner.
  • The Next.js application makes use of Server Actions.
  • The Server Action performs a redirect to a relative path which starts with a /.

* Many hosting providers (including Vercel) route requests based on the Host header, so we do not believe that this vulnerability affects any Next.js applications where routing is done in this manner.

Patches

This vulnerability was patched in #62561 and fixed in Next.js 14.1.1.

Workarounds

There are no official workarounds for this vulnerability. We recommend upgrading to Next.js 14.1.1.

Credit

Vercel and the Next.js team thank Assetnote for responsibly disclosing this issue to us, and for working with us to verify the fix. Thanks to:

Adam Kues - Assetnote
Shubham Shah - Assetnote

References

@jackwilson323 jackwilson323 published to vercel/next.js May 9, 2024
Published to the GitHub Advisory Database May 9, 2024
Reviewed May 9, 2024
Published by the National Vulnerability Database May 14, 2024
Last updated May 14, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS score

0.102%
(43rd percentile)

Weaknesses

CVE ID

CVE-2024-34351

GHSA ID

GHSA-fr5h-rqp8-mj6g

Source code

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