Threat Intelligence / CVE / CVE-2026-45321

CVE-2026-45321 — @tanstack arktype-adapter

CISA KEVRansomware
CVSS v3.1 9.6 (CRITICAL) · EPSS 15.0% (higher than 94.6% of all scored CVEs) · Priority 10/10 · Published 2026-05-12

As of 2026-05-28, CVE-2026-45321 is a CRITICAL-severity vulnerability in @tanstack arktype-adapter, CVSS v3.1 9.6, EPSS 15.0% (94.6th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-27), with a US federal remediation deadline of 2026-06-10, and CISA links it to known ransomware campaigns. Threadlinqs Intelligence links 4 tracked threat campaigns to CVE-2026-45321, most recently “Binding.gyp "Phantom Gyp" Supply Chain Attack (Miasma Worm) Enables CI/CD Worm Propagation Across 57 npm Packages”.

Last updated: 2026-05-28

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.

The record classifies CVE-2026-45321 under weakness class CWE-506. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity, availability. 10 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 124 days ago.

Severity and exploitation probability

CVSS v3.1 base score
9.6 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS (FIRST)
15.0% probability of exploitation in the next 30 days, higher than 94.6% of all scored CVEs
CISA KEV
Listed since 2026-05-27, federal remediation deadline 2026-06-10 — used in known ransomware campaigns
Threadlinqs priority
10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
Published
2026-05-12, last modified 2026-05-28

Is CVE-2026-45321 being exploited?

CISA added CVE-2026-45321 to the Known Exploited Vulnerabilities catalog on 2026-05-27, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-06-10 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. It currently carries a trending score of 44 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-45321

Because CVE-2026-45321 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-06-10. No vendor patch reference has been recorded for CVE-2026-45321 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-45321

4 tracked threats in the Threadlinqs corpus reference CVE-2026-45321, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Seeded from cveorg and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

Full detection coverage & IOCs for threats exploiting CVE-2026-45321 are available via the Threadlinqs MCP server (Purple tier). View plans →

← all vulnerabilities · Markdown version · Threadlinqs Intelligence