GHSA-qx66-fv34-fjm8
Suggest an improvement- Source
- https://github.com/advisories/GHSA-qx66-fv34-fjm8
- Import Source
- https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-qx66-fv34-fjm8/GHSA-qx66-fv34-fjm8.json
- JSON Data
- https://api.osv.dev/v1/vulns/GHSA-qx66-fv34-fjm8
- Aliases
- Published
- 2026-10-15T20:22:20Z
- Modified
- 2026-10-15T20:30:04Z
- Severity
-
- 9.3 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N CVSS Calculator
- Summary
- TanStack Router: Unauthenticated reflected XSS in TanStack Start server-function responses
- Details
-
Impact
An unauthenticated attacker can craft a URL to a server function in an affected TanStack Start app. If someone opens the link, the app can return attacker-controlled HTML from its own origin and run the attacker's JavaScript there. The script can access same-origin data available to that visitor and make requests with their authority.
Cause
The server-function transport can pass request payload fields into internal middleware state instead of limiting them to public input fields. A malformed payload can leave an attacker-controlled result in the error path. Response handling can then treat a response-shaped object as an HTTP response.
Affected versions
Published versions of
@tanstack/start-server-core,@tanstack/react-start,@tanstack/solid-start, and@tanstack/vue-startfrom1.143.12up to, but not including, their respective patched versions are affected. The patched versions are@tanstack/start-server-core@1.169.39,@tanstack/react-start@1.168.60,@tanstack/solid-start@1.168.57, and@tanstack/vue-start@1.168.56.Fix
The fix limits client-supplied server-function input to public fields and validates responses at the server boundary. Upgrade to the corresponding patched package version.
Temporary mitigations
For the configured server-function path, usually
/_serverFn/*, an edge or WAF rule can consider blocking requests without the literalx-tsr-serverFn: trueheader and browser document navigations such asSec-Fetch-Mode: navigateorAccept: text/html. A restrictive Content Security Policy on server-function responses can provide another browser-side restriction. These are mitigation suggestions, not a complete fix. The header is client-controlled and is not authentication. Test rules against legitimate GET and POST server functions and use a matching version-specific backport where possible.Credits
Lovable helped us discover and report this issue. We thank them for their help.
- Database specific
{ "cwe_ids": [ "CWE-79" ], "github_reviewed": true, "github_reviewed_at": "2026-10-15T20:22:20Z", "nvd_published_at": "2026-10-13T17:17:14Z", "severity": "CRITICAL" }- References
-
- https://github.com/TanStack/router/security/advisories/GHSA-qx66-fv34-fjm8
- https://nvd.nist.gov/vuln/detail/CVE-2026-102989
- https://github.com/TanStack/router/pull/8573
- https://github.com/TanStack/router/commit/d521abd71c69f1ff010bb3def4d417cb5fa058cb
- https://github.com/TanStack/router
- https://github.com/TanStack/router/releases/tag/release-2026-09-30-1747
Affected packages
npm / @tanstack/start-server-core
Package
- Name
- @tanstack/start-server-core
- View open source insights on deps.dev
- Purl
- pkg:npm/%40tanstack/start-server-core
npm / @tanstack/react-start
Package
- Name
- @tanstack/react-start
- View open source insights on deps.dev
- Purl
- pkg:npm/%40tanstack/react-start
npm / @tanstack/solid-start
Package
- Name
- @tanstack/solid-start
- View open source insights on deps.dev
- Purl
- pkg:npm/%40tanstack/solid-start
npm / @tanstack/vue-start
Package
- Name
- @tanstack/vue-start
- View open source insights on deps.dev
- Purl
- pkg:npm/%40tanstack/vue-start