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CVE-2026-45321: TanStack Unspecified Vulnerability

CVE-2026-45321 is rated critical with a CVSS v3.1 base score of 9.6 and affects TanStack TanStack, along with 129 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-05-27, which means exploitation in the wild has been observed.

Vulnerability description

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.

Severity breakdown

CVSS v3.1 9.6: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: Required. A user must take an action, such as opening a file or following a link.
  • Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-506: Embedded Malicious Code

The product contains code that appears to be malicious in nature.

Affected products

  • Tanstack/Arktype Adapter: 1.166.12; 1.166.15
  • Tanstack/Eslint Plugin Router: 1.161.9; 1.161.12
  • Tanstack/Eslint Plugin Start: 0.0.4; 0.0.7
  • Tanstack/History: 1.161.9; 1.161.12
  • Tanstack/Nitro V2 Vite Plugin: 1.154.12; 1.154.15
  • Tanstack/React Router: 1.169.5; 1.169.8
  • Tanstack/React Router Devtools: 1.166.16; 1.166.19
  • Tanstack/React Router Ssr Query: 1.166.15; 1.166.18
  • Tanstack/React Start: 1.167.68; 1.167.71
  • Tanstack/React Start Client: 1.166.51; 1.166.54
  • Tanstack/React Start Rsc: 0.0.47; 0.0.50
  • Tanstack/React Start Server: 1.166.55; 1.166.58
  • Tanstack/Router Cli: 1.166.46; 1.166.49
  • Tanstack/Router Core: 1.169.5; 1.169.8
  • Tanstack/Router Devtools: 1.166.16; 1.166.19

References