CVE-2026-49455 Waku: Cross-Origin CSRF on RSC Server Action Dispatch
Attackers can force victims to execute state-mutating server actions via cross-origin requests due to missing Origin validation in Waku.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-49455?
CVE-2026-49455 is a medium-severity vulnerability in wakujs waku, published on 3 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-352
Which versions are affected by CVE-2026-49455?
2 open source packages ship an affected version, including waku.
| Package | Affected | Fixed in |
|---|---|---|
waku npm | All versions | 1.0.0-beta.1 |
waku npm | All versions | 1.0.0-beta.1 |
How do I fix CVE-2026-49455?
Upgrade waku to 1.0.0-beta.1 or later.
Is CVE-2026-49455 being exploited?
There is no known exploitation of CVE-2026-49455 in the wild and no public exploit code.
Sources
Also known as GHSA-75w3-gmqx-993q.