What is CVE-2026-45321?

CVE-2026-45321 is Malware in 42 @tanstack/* packages exfiltrates cloud credentials, GitHub tokens, and SSH keys. The supplied enrichment data classifies it as Unclassified mapped to CWE-506 CWE-506.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

45 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-45321 using CVSS 9.6, EPSS 2%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

Publicly linked actor or ransomware signals in the supplied enrichment data: TeamPcp (), Ransomware use: Known. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVRansomwarecriticalpublic exploit

CVE-2026-45321

CVE-2026-45321 — Malware in 42 @tanstack/* packages exfiltrates cloud credentials, GitHub tokens, and SSH keys

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2026-45321 in CISA KEV with required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

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.

Published May 12, 2026Updated Jun 17, 2026Sources: NVD, @tanstack (CNA), CISA, FIRST EPSS, GitHub, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed May 27, 2026

EPSS

ahead of 82% of scored CVEs

Affects

@tanstack

84 products listed

CVSS base

9.6

critical

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade arktype-adapter to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Federal deadline Jun 10, 2026 — passed 100 days ago

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
@tanstack	arktype-adapter	1.166.12	Vulnerable
@tanstack	arktype-adapter	1.166.15	Vulnerable
@tanstack	eslint-plugin-router	1.161.9	Vulnerable
@tanstack	eslint-plugin-router	1.161.12	Vulnerable
@tanstack	eslint-plugin-start	0.0.4	Vulnerable
@tanstack	eslint-plugin-start	0.0.7	Vulnerable
@tanstack	history	1.161.9	Vulnerable
@tanstack	history	1.161.12	Vulnerable
@tanstack	nitro-v2-vite-plugin	1.154.12	Vulnerable
@tanstack	nitro-v2-vite-plugin	1.154.15	Vulnerable
@tanstack	react-router	1.169.5	Vulnerable
@tanstack	react-router	1.169.8	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Changed

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

Required

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
9.6	CVSS 3.1	critical	2.8	6	GitHub (CNA), @tanstack (CNA)

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

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-506 · Embedded Malicious Code

Execute Unauthorized Code or Commands::

Mitigation: Remove the malicious code and start an effort to ensure that no more malicious code exists. This may require a detailed review of all code, as it is possible to hide a serious attack in only one or two lines of code. These lines may be located almost anywhere in an application and may have been intentionally obfuscated by the attacker.::

Weakness & attack patterns

CWE-506

Inferred from the weakness class — not observed against this CVE.

T1195.001Supply Chain Compromise: Compromise Software Dependencies and Development Tools
T1195.002Supply Chain Compromise: Compromise Software Supply Chain
T1027.009Obfuscated Files or Information: Embedded Payloads

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

May 27, 2026

Federal deadline

Jun 10, 2026

passed 100 days ago

Ransomware use

Known

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1 of the 5 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

25 more posts on this CVEShowing 5 of 30 · Who is discussing this CVE, and how loudlyUnlock free

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /*, /router.
Prioritize edge telemetry for network-reachable arktype-adapter, eslint-plugin-router, eslint-plugin-start, history, nitro-v2-vite-plugin, react-router, react-router-devtools, react-router-ssr-query, react-start, react-start-client, react-start-rsc, react-start-server, router-cli, router-core, router-devtools, router-devtools-core, router-generator, router-plugin, router-ssr-query-core, router-utils, outer-vite-plugin, solid-router, solid-router-devtools, solid-router-ssr-query, solid-start, solid-start-client, solid-start-server, start-client-core, start-fn-stubs, start-plugin-core, start-server-core, start-static-server-functions, start-storage-context, valibot-adapter, virtual-file-routes, vue-router, vue-router-devtools, vue-router-ssr-query, vue-start, vue-start-client, vue-start-server, zod-adapter.
Monitor for scanner or exploit-pattern traffic after 45 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

TeamPcp

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 9.6 (AV:N)
Jun 17, 2026 · NVD
Added to CISA KEV catalog
May 27, 2026 · CISA
Initial · CVE published
May 12, 2026 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

21×SVRS was changedJun 1, 2026 – Jul 7, 2026 · SOCRadar CTI
13×TweetsMay 28, 2026 – Jun 24, 2026 · SOCRadar CTI
2×Github ReposJun 21, 2026 – Jun 25, 2026 · SOCRadar CTI
2×ModifiedMay 28, 2026 – May 29, 2026 · SOCRadar CTI

References

6 on the record

github.com/TanStack/router/issues/7383
Issue Tracking, Mitre, NIST
github.com/TanStack/router/security/advisories/GHSA-g7cv-rxg3-hmpx
Mitigation, Vendor Advisory, Mitre, NIST
tanstack.com/blog/npm-supply-chain-compromise-postmortem
Exploit, Vendor Advisory, Mitre, NIST
www.stepsecurity.io/blog/mini-shai-hulud-is-back-a-self-spreading-supply-chain-attack-hits-the-npm-ecosystem
Exploit, Third Party Advisory, Mitre, NIST
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45321
US Government Resource, NIST
nvd.nist.gov/vuln/detail/CVE-2026-45321
Vendor Advisory

Coverage

14 stories from the feeds we poll

9 more reports on this CVEShowing 5 of 14 · Vendor research and security press coverageUnlock free

Elsewhere on this site

@tanstackevery CVE for this vendor
May 2026what else CISA listed
Unclassifiedsame class
CWE-506other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-45321 is Malware in 42 @tanstack/* packages exfiltrates cloud credentials, GitHub tokens, and SSH keys, a critical vulnerability affecting arktype-adapter, eslint-plugin-router, eslint-plugin-start, history, nitro-v2-vite-plugin, react-router, react-router-devtools, react-router-ssr-query, react-start, react-start-client, react-start-rsc, react-start-server, router-cli, router-core, router-devtools, router-devtools-core, router-generator, router-plugin, router-ssr-query-core, router-utils, outer-vite-plugin, solid-router, solid-router-devtools, solid-router-ssr-query, solid-start, solid-start-client, solid-start-server, start-client-core, start-fn-stubs, start-plugin-core, start-server-core, start-static-server-functions, start-storage-context, valibot-adapter, virtual-file-routes, vue-router, vue-router-devtools, vue-router-ssr-query, vue-start, vue-start-client, vue-start-server, zod-adapter from @tanstack. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 45 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.6 describes technical severity, while EPSS 2% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.