CVE-2026-23888: pnpm: Binary ZIP extraction allows arbitrary file write via path traversal (Zip Slip)

A path traversal vulnerability in pnpm’s binary fetcher allows malicious packages to write files outside the intended extraction directory. The vulnerability has two attack vectors: (1) Malicious ZIP entries containing ../ or absolute paths that escape the extraction root via AdmZip’s extractAllTo, and (2) The BinaryResolution.prefix field is concatenated into the extraction path without validation, allowing a crafted prefix like ../../evil to redirect extracted files outside targetDir.