CVE-2026-49455
Received Received - Intake

CSRF via Unvalidated Origin in Waku React Framework

Publication date: 2026-09-03

Last updated on: 2026-09-03

Assigner: GitHub, Inc.

Description
Waku is the minimal React framework. Prior to version 1.0.0-beta.1, Waku's RSC request dispatcher invokes server actions without validating the request's Origin (or Sec-Fetch-Site) header. A cross-origin web attacker can therefore cause a victim browser to issue an authenticated POST to a registered server action endpoint using a CORS-safelisted content type (text/plain), which does not trigger a preflight. Any state-mutating server action that the application exposes via 'use server' can be invoked with the victim's cookies attached. This issue has been patched in version 1.0.0-beta.1.

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Meta Information

Published
2026-09-03
Last Modified
2026-09-03
Generated
2026-09-04
AI Q&A
2026-09-03
EPSS Evaluated
N/A
NVD
CVE-2026-49455
EUVD
EUVD-2026-70654

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
waku waku to 1.0.0-beta.1 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-352 The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.

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Executive Summary

Waku is a React framework where a vulnerability in versions before 1.0.0-beta.1 allows cross-origin attackers to trigger authenticated server actions via POST requests without proper origin validation. The attacker can bypass CORS protections using text/plain content type, which avoids preflight checks, enabling state-changing actions to execute with the victim's cookies.

Detection Guidance

This vulnerability can be detected by checking if your Waku application is running a version prior to 1.0.0-beta.1. Inspect the package version in your project dependencies or server logs. Look for unauthenticated POST requests to server action endpoints with CORS-safelisted content types like text/plain from unexpected origins.

Impact Analysis

An attacker could exploit this to perform unauthorized actions on your behalf, such as modifying data or settings, if you are logged into a vulnerable Waku application. This could lead to account takeover, data leaks, or other malicious changes without your knowledge.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's integrity and confidentiality principles or HIPAA's safeguards for protected health information. Organizations using vulnerable Waku versions may face compliance failures and legal consequences.

Mitigation Strategies

Upgrade Waku to version 1.0.0-beta.1 or later immediately. Review server actions to ensure they do not expose sensitive state-mutating operations. Implement strict Origin or Sec-Fetch-Site header validation in the RSC request dispatcher to block cross-origin requests.

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