CVE-2026-126355honojs hono cross-site request forgery
CVE-2026-126355 is a cross-site request forgery in honojs hono, rated medium (5.3 on CVSS 3.1).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Deferred
What it is
Another site can make a signed-in user's browser send a request the user never meant to send.
How it is reached
An attacker can exploit it over the network, without an account, but someone has to act first, such as opening a file or following a link. Success also depends on conditions the attacker does not fully control.
What an attacker gains
A successful attack can change data or behaviour. In practice, this kind of flaw lets an attacker act inside a signed-in user's browser session.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- Upgrade honojs hono to 4.13.16 or later.
- Until it is patched, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
- Warn the people who use it, and filter files and links on the way in.
Description from NVD
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.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Web front ends and single-page apps. The flaw sits between a user's browser and the web application.
- Admin consoles served to a browser. The flaw sits between a user's browser and the web application.
Trust boundaries in play
- Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
- People who open files and links. Mail, chat and browsers are the delivery path.
- Between a user's browser and the web application. An attacker who crosses it can act inside a signed-in user's browser session.
Questions to answer about your own systems
- Where does honojs hono run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.