Security readout for executives and security teams
Plain-English summary
Malicious releases were published under trusted @tanstack package names for a short window on May 11, 2026. The malware targeted cloud credentials, GitHub tokens, and SSH keys. This is a supply-chain incident, so business risk depends on whether affected versions were installed in developer, CI, or production build environments.
Executive priority
Treat this as an urgent supply-chain credential exposure event. Prioritize inventory, containment, and secret rotation for systems that consumed affected packages, especially CI and developer environments with cloud or source-control access.
Technical view
Sources describe 84 malicious versions across 42 @tanstack/* npm packages, published via a legitimate GitHub Actions OIDC trusted-publisher path. The attack chained pull_request_target misuse, cache poisoning across fork and base workflows, and runtime OIDC token extraction from the Actions runner process.
Likely exposure
Highest exposure is in organizations that installed affected @tanstack versions during or after the May 11, 2026 publication window. CI runners, developer workstations, and build systems are especially sensitive because the malware sought cloud credentials, GitHub tokens, and SSH keys.
Exploitation context
CISA KEV status indicates known exploitation. The bundle describes malicious npm versions published under trusted identity, not just a theoretical weakness. It does not prove every downstream consumer was compromised, so validation should focus on package inventory, install timing, and secret exposure paths.
Researcher notes
The notable issue is trusted-publisher abuse without a modified publish workflow. Evidence points to a chain involving pull_request_target trust misuse, cache poisoning, and Actions runner OIDC token extraction. The provided affected list is partial relative to the stated 42 packages.
Mitigation direction
- Identify and remove affected @tanstack package versions from manifests and lockfiles.
- Follow the TanStack advisory for known-good package versions and cleanup guidance.
- Rotate cloud credentials, GitHub tokens, and SSH keys exposed on affected systems.
- Rebuild affected CI runners and developer environments from trusted baselines.
- Review GitHub Actions OIDC, cache, and pull_request_target workflow controls.
- Monitor vendor, npm, and CISA guidance for updates.
Validation and detection
- Search dependency manifests and lockfiles for affected @tanstack versions.
- Check build logs for installs during the May 11, 2026 malicious publication window.
- Review CI and workstation logs for unexpected credential access or outbound activity.
- Inventory secrets available to affected build and developer environments.
- Confirm rotated credentials are no longer accepted in cloud, GitHub, and SSH systems.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-506: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-45321 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.6 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H2.86GitHub_MVulnerability scoring details
Base CVSS 3.1 score
9.6CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2026-45321 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-05-27T00:00:00.000Z: CVE-2026-45321 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/TanStack/router/security/advisories/GHSA-g7cv-rxg3-hmpxCVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/TanStack/router/issues/7383CVE reference, GitHub_M · x_refsource_MISC
- https://tanstack.com/blog/npm-supply-chain-compromise-postmortemCVE reference, GitHub_M · x_refsource_MISC
- https://www.stepsecurity.io/blog/mini-shai-hulud-is-back-a-self-spreading-supply-chain-attack-hits-the-npm-ecosystemCVE reference, GitHub_M · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-45321CVE reference, CISA-ADP · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Embedded Malicious Code
Embedded Malicious Code represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.