Vulnerability · Published Oct 13, 2026 · Assigned by GitHub_M
CVE-2026-102989TanStack Router: Unauthenticated reflected XSS in TanStack Start server-function responses
Critical 9.3
In plain English
A critical-severity cross-site scripting in react-start from @tanstack. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
TanStack Router is a client-first, server-capable, fully type-safe router and full-stack framework for the web. From 1.143.12 until 1.169.39 for @tanstack/start-server-core, 1.168.60 for @tanstack/react-start, 1.168.57 for @tanstack/solid-start, and 1.168.56 for @tanstack/vue-start, an unauthenticated attacker can place non-public fields in a server-function request payload so that attacker-controlled middleware state reaches the error path and a response-shaped object is accepted as an HTTP response. A crafted server-function URL can therefore return attacker-controlled HTML from the application's origin; when a visitor opens the URL, the injected script can access same-origin data and issue requests with the visitor's authority. This issue is fixed in @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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @tanstack/react-start | 1.168.60 | GHSA-qx66-fv34-fjm8 |
| npm | @tanstack/solid-start | 1.168.57 | GHSA-qx66-fv34-fjm8 |
| npm | @tanstack/start-server-core | 1.169.39 | GHSA-qx66-fv34-fjm8 |
| npm | @tanstack/vue-start | 1.168.56 | GHSA-qx66-fv34-fjm8 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| TanStack | router | < release-2026-09-30-1747 |
| @tanstack | react-start | >= 1.143.12, < 1.168.60 |
| @tanstack | solid-start | >= 1.143.12, < 1.168.57 |
| @tanstack | start-server-core | >= 1.143.12, < 1.169.39 |
| @tanstack | vue-start | >= 1.143.12, < 1.168.56 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
References
- https://github.com/TanStack/router/security/advisories/GHSA-qx66-fv34-fjm8 x_refsource_CONFIRM
- https://github.com/TanStack/router/pull/8573 x_refsource_MISC
- https://github.com/TanStack/router/commit/d521abd71c69f1ff010bb3def4d417cb5fa058cb x_refsource_MISC
- https://github.com/TanStack/router/releases/tag/release-2026-09-30-1747 x_refsource_MISC