MAL-2026-13624 Malicious code in @depup/memfs (npm)

This package is an automated 'DepUp' republish of memfs whose lib/index.js and lib/index.d.ts have been stripped of the upstream source and rewritten to require nine '@jsonjoy.com/fs-' packages (fs-node, fs-core, fs-node-utils, fs-fsa, fs-node-to-fsa, fs-fsa-to-node, fs-print, fs-snapshot, fs-node-builtins), all pinned to 4.67.0 — a version tag that matches memfs itself rather than any real release history of those names. Upstream memfs bundles its own source and does not depend on these packages. The republished lib/index.js contains only require() calls to the '@jsonjoy.com/fs-' names, so installing this package and importing memfs resolves and executes whatever code is published under those names at 4.67.0. The package.json 'depup.changes' metadata also records bumping @jsonjoy.com/json-pack and @jsonjoy.com/util from ^1.11.0/^1.9.0 to ^18.28.0, non-contiguous jumps well beyond the real published range of those libraries, consistent with steering the resolver toward attacker-published versions. Installing or requiring @depup/memfs pulls in and runs code from a set of newly-introduced dependency names controlled by the republisher, with no lifecycle hook needed — a dependency-chain dropper shape via a memfs lookalike.