Advisories for Npm/@Tanstack/Start-Server-Core package

On May 19th 2026, a new supply chain attack linked to the Mini Shai-Hulud campaign was identified. This package contains malicious code published through a compromised npm maintainer account. The malicious software is part of a coordinated high-volume publish wave targeting popular data visualization and charting ecosystems. It is recommended that all credentials be rotated, npm cache is cleared, the node_modules directory is removed, and all dependencies be rolled back …

A type-confusion bug in seroval ≤ 1.5.2 (upstream advisory) allowed a crafted JSON body sent to one TanStack Start server function to trigger invocation of a different client-referenced server function as a side effect of deserializing the request payload. This is not an authentication bypass and not remote code execution. The mechanism only invokes server functions that the same client could already reach directly via /_serverFn/, and the target function's …

On 2026-05-11, between approximately 19:20 and 19:26 UTC, 84 malicious versions across 42 @tanstack/* packages were published to the npm registry. The publishes were authenticated via the legitimate GitHub Actions OIDC trusted-publisher binding for TanStack/router, but the publish workflow itself was not modified. The attacker chained three known vulnerability classes — a pull_request_target "Pwn Request" misconfiguration, GitHub Actions cache poisoning across the fork↔base trust boundary, and runtime memory extraction of …