CVE-2026-49455

MEDIUMCVSS 6.5/10EPSS 0.12%

Last modified

CVE-2026-49455 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.12% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.12%

2.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
wakujswaku< 1.0.0-beta.1

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-49455?
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.
How severe is CVE-2026-49455?
CVE-2026-49455 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.
How do I fix CVE-2026-49455?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST