CVE-2026-126355
Deferred Deferred - Pending Action

CSRF Bypass via Hyperlink Auditing in Hono

Publication date: 2026-11-13

Last updated on: 2026-11-13

Assigner: GitHub, Inc.

Description
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.16, csrf() limits origin validation to the content types normally sent by HTML forms and therefore does not validate text/ping requests generated by Chromium hyperlink auditing. Chrome and Edge can send a cross-origin credentialed POST without a CORS preflight through an <a ping> action, and the middleware then skips both Origin and Sec-Fetch-Site checks. The fixed request body limits exploitation to state-changing endpoints whose effect is selected by the path or query string and does not depend on submitted body data. The user's cookie must accompany the request, which generally requires a same-site origin or a cookie configured with SameSite=None, and Firefox does not send hyperlink-auditing pings by default. This issue is fixed in version 4.13.16.

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Meta Information

Published
2026-11-13
Last Modified
2026-11-13
Generated
2026-11-13
AI Q&A
2026-11-13
EPSS Evaluated
N/A
NVD
CVE-2026-126355

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
honojs hono to 4.13.16 (exc)

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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

This vulnerability affects the Hono web framework's CSRF middleware. Before version 4.13.16, the middleware only validated certain content types used by HTML forms. It did not recognize text/ping requests generated by Chromium's hyperlink auditing feature (<a ping>). This allowed cross-origin POST requests with user cookies to bypass CSRF protection, potentially enabling state-changing actions on vulnerable applications.

Detection Guidance

To detect this vulnerability, check if your Hono framework version is below 4.13.16. Use commands like 'npm list hono' or 'grep version package.json' in your project directory. Monitor network traffic for POST requests with 'Content-Type: text/ping' to endpoints that should require CSRF protection.

Impact Analysis

An attacker could trick a logged-in user into triggering unwanted actions like logging out or deleting resources on a vulnerable application. The attack requires the user's session cookies to be sent and works best with SameSite=None cookies. Firefox users are less affected as it does not support hyperlink auditing by default.

Compliance Impact

This CSRF vulnerability could lead to unauthorized state changes in applications, potentially violating data integrity and access control requirements under GDPR and HIPAA. Unauthorized actions may result in unauthorized data access or modification, which could breach compliance obligations for protecting sensitive data.

Mitigation Strategies

Upgrade Hono to version 4.13.16 or later immediately. Add middleware to explicitly reject requests with 'Content-Type: text/ping' before the CSRF middleware. Configure session cookies with 'SameSite=Strict' to prevent cross-site requests from including credentials.

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