CVE-2026-45321
TanStack Unspecified Vulnerability
TanStack TanStack
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.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 27 May 2026. US federal agencies were required to remediate it by 10 June 2026. CISA records this vulnerability as known to be used in ransomware campaigns.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 2.3%, which is higher than 82% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Frequently asked questions
Is CVE-2026-45321 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2026-45321.
What does CVE-2026-45321 affect?
CVE-2026-45321 affects TanStack TanStack. 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 is rated CRITICAL with a CVSS base score of 9.6. EPSS puts the probability of exploitation in the next 30 days at 2.3%, higher than 82% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 10 June 2026.
How should organisations respond to CVE-2026-45321?
Apply the vendor patch for TanStack TanStack as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.