TanStack Unspecified Vulnerability
@tanstack — arktype-adapter
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.
9.6
2.3%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- Published
- May 12, 2026
- Modified
- May 28, 2026
- Added to KEV
- May 27, 2026
- Federal patch due
- Jun 10, 2026
CISA required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2026-45321, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2026-45321 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is CVE-2026-45321?
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.
How severe is CVE-2026-45321?
CVE-2026-45321 has a CVSS base score of 9.6 out of 10 (CVSS 3.1).
Is CVE-2026-45321 actively exploited in the wild?
Yes. CVE-2026-45321 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added May 27, 2026, meaning CISA has confirmed evidence of active exploitation. It is also flagged as used in ransomware campaigns.
What is the EPSS score for CVE-2026-45321?
2.3% - meaning FIRST.org's EPSS model estimates a 2.3% probability this vulnerability will be exploited in the wild within 30 days (82% percentile among all scored CVEs).
What type of vulnerability is CVE-2026-45321?
CVE-2026-45321 is classified under CWE-506 (CWE-506: Embedded Malicious Code).
Cross-checked against
Impactr finds and proves whether CVE-2026-45321 - or flaws like it - are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.
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