Have exploitation attempts been observed for CVE-2026-45321?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists CVE-2026-45321 as a known exploited vulnerability. Confidence is confirmed.

What exploitation activity has Previdian observed?

Previdian has not yet recorded sensor-observed exploitation attempts for CVE-2026-45321. Our sensors continue to monitor for activity targeting this CVE.

Which versions are affected?

CVE-2026-45321 affects @tanstack arktype-adapter and 41 other products. Previdian lists 84 version rows; examples include 1.166.12, 1.166.15, and 1.161.9.

Yes. CVE-2026-45321 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Added to Previdian from a trusted third-party report 1 day before CISA listed it.

Vulnerability report

Exploitation attempts observed in the wild Confirmed confidence In CISA KEV

CVE-2026-45321

arktype-adapter

@tanstack / arktype-adapter · 1.166.12

Watch CVE-2026-45321 Browse KEV feed

Severity: CVSS 9.6 · Critical
Confidence: Confirmed
Exploit status: Exploitation attempts observed in the wild
EPSS: 1.1%
First observed: —
Last observed: —

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-45321 is an unauthenticated vulnerability affecting @tanstack arktype-adapter and 41 other products. On 2026-05-11, between approximately 19:20 and 19:26 UTC, 84 malicious versions across 42 @tanstack/*...

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Listed in CISA KEV. Also reported by third-party sources. Confidence is confirmed.

Who is affected?

@tanstack / arktype-adapter 1.166.12.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

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.

Vendor Product Affected Status

@tanstack Affected

arktype-adapter

1.166.12 1.166.15

Affected

@tanstack Affected

eslint-plugin-router

1.161.9 1.161.12

Affected

@tanstack Affected

eslint-plugin-start

0.0.4 0.0.7

Affected

@tanstack Affected

history

1.161.9 1.161.12

Affected

@tanstack Affected

nitro-v2-vite-plugin

1.154.12 1.154.15

Affected

@tanstack Affected

react-router

1.169.5 1.169.8

Affected

@tanstack Affected

react-router-devtools

1.166.16 1.166.19

Affected

@tanstack Affected

react-router-ssr-query

1.166.15 1.166.18

Affected

@tanstack Affected

react-start

1.167.68 1.167.71

Affected

@tanstack Affected

react-start-client

1.166.51 1.166.54

Affected

@tanstack Affected

react-start-rsc

0.0.47 0.0.50

Affected

@tanstack Affected

react-start-server

1.166.55 1.166.58

Affected

@tanstack Affected

router-cli

1.166.46 1.166.49

Affected

@tanstack Affected

router-core

1.169.5 1.169.8

Affected

@tanstack Affected

router-devtools

1.166.16 1.166.19

Affected

@tanstack Affected

router-devtools-core

1.167.6 1.167.9

Affected

@tanstack Affected

router-generator

1.166.45 1.166.48

Affected

@tanstack Affected

router-plugin

1.167.38 1.167.41

Affected

@tanstack Affected

router-ssr-query-core

1.168.3 1.168.6

Affected

@tanstack Affected

router-utils

1.161.11 1.161.14

Affected

@tanstack Affected

outer-vite-plugin

1.166.53 1.166.56

Affected

@tanstack Affected

solid-router

1.169.5 1.169.8

Affected

@tanstack Affected

solid-router-devtools

1.166.16 1.166.19

Affected

@tanstack Affected

solid-router-ssr-query

1.166.15 1.166.18

Affected

@tanstack Affected

solid-start

1.167.65 1.167.68

Affected

@tanstack Affected

solid-start-client

1.166.50 1.166.53

Affected

@tanstack Affected

solid-start-server

1.166.54 1.166.57

Affected

@tanstack Affected

start-client-core

1.168.5 1.168.8

Affected

@tanstack Affected

start-fn-stubs

1.161.9 1.161.12

Affected

@tanstack Affected

start-plugin-core

1.169.23 1.169.26

Affected

@tanstack Affected

start-server-core

1.167.33 1.167.36

Affected

@tanstack Affected

start-static-server-functions

1.166.44 1.166.47

Affected

@tanstack Affected

start-storage-context

1.166.38 1.166.41

Affected

@tanstack Affected

valibot-adapter

1.166.12 1.166.15

Affected

@tanstack Affected

virtual-file-routes

1.161.10 1.161.13

Affected

@tanstack Affected

vue-router

1.169.5 1.169.8

Affected

@tanstack Affected

vue-router-devtools

1.166.16 1.166.19

Affected

@tanstack Affected

vue-router-ssr-query

1.166.15 1.166.18

Affected

@tanstack Affected

vue-start

1.167.61 1.167.64

Affected

@tanstack Affected

vue-start-client

1.166.46 1.166.49

Affected

@tanstack Affected

vue-start-server

1.166.50 1.166.53

Affected

@tanstack Affected

zod-adapter

1.166.12 1.166.15

Affected

Published: 12 May 2026
Exploitation Attempts Reported: 01 Jun 2026
Attack vector: Remote
Complexity: Low
Privileges: None
User interaction: Required

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-45321
https://github.com/TanStack/router/security/advisories/GHSA-g7cv-rxg3-hmpx github.com · CVE Record https://github.com/TanStack/router/security/advisories/GHSA-g7cv-rxg3...
https://github.com/TanStack/router/issues/7383 github.com · CVE Record https://github.com/TanStack/router/issues/7383
https://tanstack.com/blog/npm-supply-chain-compromise-postmortem tanstack.com · CVE Record https://tanstack.com/blog/npm-supply-chain-compromise-postmortem
https://www.stepsecurity.io/blog/mini-shai-hulud-is-back-a-self-spreading-supply-chain-attack-hits-the-npm-ecosystem stepsecurity.io · CVE Record https://www.stepsecurity.io/blog/mini-shai-hulud-is-back-a-self-sprea...

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation attempts observed in the wild

CVE

Recorded 01 Jun 2026

A trusted third party reported exploitation attempts.

Targeted by malware-related exploitation attempts

CVE

Recorded 02 Jun 2026

Exploitation attempts against this vulnerability are associated with malware-related payloads.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access

Source	Added
The Shadowserver First	2026-05-27 18:00 UTC
CVE	2026-06-01 10:27 UTC
CISA	2026-06-02 14:00 UTC
All CISA Advisories	2026-06-02 14:21 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts: 0; 0; 0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.6 Critical

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS

1.1%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Embedded Malicious Code CWE-506

Recent mention · The Hacker News

19 Sep 2026

CrowdSec Says TanStack npm Attack Led to Copy of 170 Private GitHub Repositories

An attacker copied about 170 of CrowdSec's private GitHub repositories on May 22 using the account of an employee who had just left, CrowdSec said on September 18. The French security company had kept his GitHub access open. CrowdSec says his laptop was compromised in...

Read full advisory

All Mentions

Recent mention · The Hacker News

CrowdSec Says TanStack npm Attack Led to Copy of 170 Private GitHub Repositories

The Hacker News · 19 Sep 2026

Recent mention · All CISA Advisories

CISA Adds Three Known Exploited Vulnerabilities to Catalog

All CISA Advisories · 27 May 2026

CISA has added three new vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, based on evidence of active exploitation. CVE-2026-8398 Daemon Tools Lite Embedded Malicious Code Vulnerability CVE-2026-45321 TanStack Unspecified Vulnerability CVE-2026-48027 Nx Console Embedded Malicious Code Vulnerability These types of vulnerabilities are frequent attack vectors for malicious cyber actors and pose significant risks to the federal enterprise. Binding Operational Directive (BOD) 22-01: Reducing the Significant Risk of Known Exploited Vulnerabilities established the KEV...

Timeline

From disclosure to observed exploitation attempts

02 Jun 2026
14:21 UTC

KEV confirmed by All CISA Advisories

Exploitation attempts reported by an external source
02 Jun 2026
14:00 UTC

Targeted by malware-related exploitation attempts

Malware-related exploitation attempts or payloads reported
02 Jun 2026
14:00 UTC

Added to CISA KEV

Listed in the CISA Known Exploited Vulnerabilities catalog
01 Jun 2026
10:27 UTC

KEV confirmed by CVE

Exploitation attempts reported by an external source
27 May 2026
18:00 UTC

Added to Previdian KEV Feed

High-confidence, third-party report of exploitation attempts
12 May 2026
00:12 UTC

CVE published

Vulnerability disclosed publicly
11 May 2026
20:50 UTC

CVE ID reserved

Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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Evidence confidence and provenance
First-party sensor telemetry
PoC and scanner references
Affected versions and enrichment
Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-45321

Sample API response

{
  "cve_id": "CVE-2026-45321",
  "confidence": "Confirmed",
  "cvss_score": 9.6,
  "cvss_estimated": false,
  "epss_score": 0.01054,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

CVE-2026-45321

arktype-adapter

Tags

CVE References

Exploitation attempts observed in the wild

Targeted by malware-related exploitation attempts

Known exploited vulnerability sources

Observed signals

Scanner coverage

Virtual patch status

Weaknesses

CrowdSec Says TanStack npm Attack Led to Copy of 170 Private GitHub Repositories

All Mentions

KEV confirmed by All CISA Advisories

Targeted by malware-related exploitation attempts

Added to CISA KEV

KEV confirmed by CVE

Added to Previdian KEV Feed

CVE published

CVE ID reserved

Automate this intelligence