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Medium

Waku: Cross-Origin CSRF on RSC Server Action Dispatch

Type: advisorySources: OSV

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-49455
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 15:10 UTC · Revision 1

Source evidence

Waku: Cross-Origin CSRF on RSC Server Action Dispatch

core-osv · Original source

Published 3 Sept 2026, 18:15 UTC

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.

osv:CVE-2026-49455
Complete source record
{
  "id": "17ee456366aa4f0aea09e12ca9eca2cee71f9420236f51a05d3717ff15877155",
  "url": "https://osv.dev/vulnerability/CVE-2026-49455",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Waku: Cross-Origin CSRF on RSC Server Action Dispatch",
    "summary": "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.",
    "evidence": "osv:CVE-2026-49455",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-49455",
      "aliases": [
        "CVE-2026-49455",
        "GHSA-75w3-gmqx-993q"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/wakujs/waku",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5a5f4a48ba18c004d4552cbee15d0e3e1f8ea371"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.0.0-beta.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5a5f4a48ba18c004d4552cbee15d0e3e1f8ea371"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.0.0-beta.1"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.0.0-beta.1"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49455.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.824933014Z",
      "provider": "osv",
      "references": [
        "https://github.com/wakujs/waku/releases/tag/v1.0.0-beta.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49455.json",
        "https://github.com/wakujs/waku/security/advisories/GHSA-75w3-gmqx-993q",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-49455"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-352"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49455.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-49455",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496692,
  "published_at": "2026-09-03T18:15:42.014+00:00"
}