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/*...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2026-45321
arktype-adapter
@tanstack / arktype-adapter · 1.166.12
- Severity
- CVSS 9.6 · Critical
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 2.3%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. 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
arktype-adapter
1.166.12
Affected
@tanstack
arktype-adapter
1.166.15
Affected
@tanstack
eslint-plugin-router
1.161.9
Affected
@tanstack
eslint-plugin-router
1.161.12
Affected
@tanstack
eslint-plugin-start
0.0.4
Affected
@tanstack
eslint-plugin-start
0.0.7
Affected
@tanstack
history
1.161.9
Affected
@tanstack
history
1.161.12
Affected
@tanstack
nitro-v2-vite-plugin
1.154.12
Affected
@tanstack
nitro-v2-vite-plugin
1.154.15
Affected
@tanstack
react-router
1.169.5
Affected
@tanstack
react-router
1.169.8
Affected
@tanstack
react-router-devtools
1.166.16
Affected
@tanstack
react-router-devtools
1.166.19
Affected
@tanstack
react-router-ssr-query
1.166.15
Affected
@tanstack
react-router-ssr-query
1.166.18
Affected
@tanstack
react-start
1.167.68
Affected
@tanstack
react-start
1.167.71
Affected
@tanstack
react-start-client
1.166.51
Affected
@tanstack
react-start-client
1.166.54
Affected
@tanstack
react-start-rsc
0.0.47
Affected
@tanstack
react-start-rsc
0.0.50
Affected
@tanstack
react-start-server
1.166.55
Affected
@tanstack
react-start-server
1.166.58
Affected
@tanstack
router-cli
1.166.46
Affected
- Published
- 12 May 2026
- Exploitation Reported
- 01 Jun 2026
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
Tags
edge
cisa
malware
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
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CVE
Independent exploitation attestation added to the KEV Intelligence record.
Used in malware
CVE
Malware families have been linked to exploitation of this CVE.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence 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
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No KEV Intelligence 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
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
EPSS
2.3%
Weaknesses
Recent mention · All CISA Advisories
CISA Adds Three Known Exploited Vulnerabilities to Catalog
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...
Read full advisoryTimeline
From disclosure to observed exploitation
-
KEV confirmed by All CISA Advisories
Exploitation attested by an external source
-
First public exploitation report
Exploit observed in malware
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
KEV confirmed by CVE
Exploitation attested by an external source
-
Added to KEV Intelligence KEV Feed
High-confidence, third-party attested exploitation
-
CVE published
Vulnerability disclosed publicly
-
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.
- 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
Free JSON includes basic KEV fields{
"cve_id": "CVE-2026-45321",
"confidence": "Confirmed",
"cvss_score": 9.6,
"cvss_estimated": false,
"epss_score": 0.02342,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
Get alerts on high-impact exploitation
Receive curator-selected alerts when exploitation activity warrants attention. Each alert includes the evidence and context needed to decide what requires attention now.