CVE-2026-45321

CVE-2026-45321 is a supply chain compromise in which 84 malicious versions across 42 @tanstack/* npm packages (including @tanstack/react-router, @tanstack/react-start, @tanstack/history, and related router/start packages) were published to the npm registry on 2026-05-11 between roughly 19:20 and 19:26 UTC, authenticated through TanStack's legitimate GitHub Actions OIDC trusted-publisher binding. The attacker chained three known weakness classes — a pull_request_target 'Pwn Request' misconfiguration, GitHub Actions cache poisoning across the fork-to-base trust boundary, and runtime memory extraction of the OIDC token from the Actions runner process — allowing publication under a trusted identity without modifying the publish workflow. Each affected package received exactly two malicious versions carrying credential-stealing malware, so developers, CI pipelines, or downstream builds that installed them could have npm, GitHub, and cloud credentials extracted; related reporting (FBI, StepSecurity) links the campaign to stolen cloud credentials and a self-spreading 'Mini Shai-Hulud' worm that also hit packages in other ecosystems such as Mistral AI and Guardrails AI. Exposure is limited to consumers who installed the two malicious versions published per package during the exposure window; other users of these widely deployed libraries were not affected by the malicious publishes. Exploitation is confirmed in the wild: the issue was added to CISA's Known Exploited Vulnerabilities catalog on 2026-05-27 with known ransomware use, and EPSS estimates a 2.3% probability of exploitation in the next 30 days (83rd percentile).

What to do: Audit lockfiles and CI logs for the affected @tanstack/* packages' versions published during the 2026-05-11 ~19:20-19:26 UTC window; if found, reinstall from clean versions per the TanStack postmortem (tanstack.com/blog/npm-supply-chain-compromise-postmortem) and rotate exposed credentials (npm tokens, GitHub PATs/secrets, cloud keys), treating any cached CI artifacts as suspect. Apply mitigations per vendor instructions and CISA BOD 22-01 guidance for cloud services, or discontinue use if mitigations are unavailable, and remediate the underlying CI weaknesses (pull_request_target handling, Actions cache hygiene, and OIDC token handling) to prevent recurrence.