Junglewise Threat Intelligence

CVE-2026-9496: npm pacote Denial of Service in addGitSha function

CVE-2026-9496 · Severity: high · CVSS 7.5 · Published 2026-05-26

Vendors: npm.

Executive brief

npm pacote is a package fetcher used in the Node.js ecosystem to download and manage npm dependencies. A flaw in the addGitSha function allows an attacker to send a crafted input that causes the tool to consume excessive CPU resources, effectively freezing or crashing systems that rely on it. This could disrupt CI/CD pipelines, package installations, and automated dependency management across organizations.

Technical details

The vulnerability is a resource-exhaustion flaw (CWE-400 and CWE-1333) in the addGitSha function of pacote. When processing a specially crafted spec.rawSpec parameter, the function's regex replacement and string-manipulation logic enters a pathological state, consuming excessive CPU cycles and potentially causing denial of service. The attack vector is network-based with no authentication or user interaction required. An attacker can trigger this by directly calling pacote with a malicious spec or by hosting a malicious package in a registry. Pacote versions 11.2.7 through 21.5.0 are affected; the fix is available in version 21.5.1 and later.

Affected products

  • npm pacote >= 11.2.7, < 21.5.1

Timeline

  • 2026-05-26: disclosed: Published to GitHub Advisory Database
  • 2026-05-26: patched: Patched in version 21.5.1

References