CVE-2026-45321 describes a supply chain attack on the @tanstack npm packages, including arktype-adapter, where an attacker leveraged a combination of a pull_request_target misconfiguration, GitHub Actions cache poisoning, and runtime memory extraction of OIDC tokens to publish malicious versions under a trusted identity. This attack resulted in 84 malicious versions being published across 42 packages, each receiving two malicious versions. The attack exploited the trusted GitHub Actions OIDC publisher binding without modifying the publish workflow itself. The affected versions of @tanstack/arktype-adapter are exactly 1.166.12 and 1.166.15. The CVSS score is 9.6 (critical), indicating high impact on confidentiality, integrity, and availability.

The attack allows an adversary to publish malicious code under a trusted identity, potentially leading to credential theft and compromise of systems that consume the affected packages. The high CVSS score (9.6) reflects critical impact on confidentiality, integrity, and availability. This compromises the software supply chain trust for the affected @tanstack packages, including arktype-adapter versions 1.166.12 and 1.166.15.

No official patch or remediation level has been provided yet. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should avoid using the affected versions (=1.166.12 and =1.166.15) of @tanstack/arktype-adapter and related packages. Monitor vendor channels for updates and consider verifying package integrity through alternative means.