CVE-2026-101044: pacquet before 12.0.0-alpha.5 Path Traversal via lockfile alias

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-27 · updated 2026-09-30
Weakness: CWE-22

Description

pacquet, the Rust package-manager component shipped in the pnpm npm package versions >=12.0.0-alpha.0 and <12.0.0-alpha.5, does not validate dependency alias/name paths taken from a lockfile before using them in install-time filesystem joins. When a user installs a project with an attacker-supplied lockfile using --trust-lockfile or a frozen lockfile, alias entries containing path traversal segments (for example '../../escaped-link') are used when creating dependency and package links, bin destinations, hoisted entries, and virtual-store slots, allowing symlinks and directories to be created outside the intended project and node_modules boundary. Version 12.0.0-alpha.5 validates dependency names and every virtual-store slot path with a shared safe-join containment helper before any filesystem materialization, rejecting traversal, absolute, platform-specific, and reserved names with ERR_PNPM_INVALID_DEPENDENCY_NAME.

Affected products

pnpm: from 12.0.0-alpha.0 before 12.0.0-alpha.5 — fixed in 12.0.0-alpha.5

How to fix

Upgrade to a fixed version: pnpm 12.0.0-alpha.5. Check the vendor advisory for mitigations.

References

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