TanStack · TanStack · TanStack Unspecified Vulnerability
Verdict
Patch soon · actively exploited, reachable from the internet without credentials, and in the top half of CVEs by near-term exploitation probability
Added to CISA KEV 2026-05-27 · exploited in the wild for 123 days · used in ransomware campaigns
CVSS 9.6 CRITICAL. The score is a summary; these three components are the part that decides whether something scanning the internet can use it.
| Attack vector | networkreachable over the network, with no local access needed |
|---|---|
| Privileges required | noneneeds no credentials at all |
| User interaction | requiredneeds a user to click, load or submit something first |
| Base vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H |
| Weakness | CWE-506 |
This describes the vulnerability. It says nothing about whether your systems run it.
EPSS puts the probability of exploitation in the next 30 days at 0.0105, which places it in the top half of all tracked CVEs. The percentile is the more useful half: 0.18 in absolute terms sounds low until you know most of the internet-facing software in the world scores under that.
| EPSS probability | 0.0105 |
|---|---|
| Percentile | 0.630 — top half |
| Added to KEV | 2026-05-27 |
|---|---|
| Days exploited | 123 |
| Federal remediation due | not set |
| Ransomware use | known to be used in ransomware campaigns |
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
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 the OIDC token from the Actions runner process — to publish credential-stealing malware under a trusted identity. Each affected package received exactly two malicious versions, published a few minutes apart.