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[ CVE-2026-102989 · Published 13 Oct 2026 ]

TanStack Router: Unauthenticated reflected XSS in TanStack Start server-function responses

CVSS 9.3 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Critical severity: CVSS 9.3

[ Description ]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.

[ Fixes ]Fixes and patches

  • @tanstack/start-server-core 1.169.39Fixed version · GitHub Advisories · npm package @tanstack/start-server-core: upgrade to 1.169.39 or later (affected >= 1.143.12, < 1.169.39)
  • @tanstack/react-start 1.168.60Fixed version · GitHub Advisories · npm package @tanstack/react-start: upgrade to 1.168.60 or later (affected >= 1.143.12, < 1.168.60)
  • @tanstack/solid-start 1.168.57Fixed version · GitHub Advisories · npm package @tanstack/solid-start: upgrade to 1.168.57 or later (affected >= 1.143.12, < 1.168.57)
  • @tanstack/vue-start 1.168.56Fixed version · GitHub Advisories · npm package @tanstack/vue-start: upgrade to 1.168.56 or later (affected >= 1.143.12, < 1.168.56)

[ Packages ]Affected open-source packages

  • @tanstack/start-server-core npmAffected >= 1.143.12, < 1.169.39 · fixed in 1.169.39 · GHSA-qx66-fv34-fjm8
  • @tanstack/react-start npmAffected >= 1.143.12, < 1.168.60 · fixed in 1.168.60 · GHSA-qx66-fv34-fjm8
  • @tanstack/solid-start npmAffected >= 1.143.12, < 1.168.57 · fixed in 1.168.57 · GHSA-qx66-fv34-fjm8
  • @tanstack/vue-start npmAffected >= 1.143.12, < 1.168.56 · fixed in 1.168.56 · GHSA-qx66-fv34-fjm8

[ References ]References