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GHSA-mq59-m269-xvcx

MediumCVSS 5.3 / 10
Published Mar 17, 2026·Last modified Mar 19, 2026
Affected Components(0)

No affected components available

Description

Summary

origin: null was treated as a "missing" origin during Server Action CSRF validation. As a result, requests from opaque contexts (such as sandboxed iframes) could bypass origin verification instead of being validated as cross-origin requests.

Impact

An attacker could induce a victim browser to submit Server Actions from a sandboxed context, potentially executing state-changing actions with victim credentials (CSRF).

Patches

Fixed by treating 'null' as an explicit origin value and enforcing host/origin checks unless 'null' is explicitly allowlisted in experimental.serverActions.allowedOrigins.

Workarounds

If upgrade is not immediately possible:

  • Add CSRF tokens for sensitive Server Actions.
  • Prefer SameSite=Strict on sensitive auth cookies.
  • Do not allow 'null' in serverActions.allowedOrigins unless intentionally required and additionally protected.
Risk Scores
Base Score
5.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights.

Threat Intelligence
1.3

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
0.20%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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