Node.js v26.4.0 adds a virtual file system and TLS certificate compression

Sources: GitHub release
Summary: Node.js published v26.4.0 on the Current line on 2026-06-24. New semver-minor features include a minimal node:vfs subsystem with node:fs/promises dispatch to mounted instances, package maps in the module loader, a certificateCompression option for TLS, caller-supplied buffers in readFile(), and TCP_KEEPINTVL/TCP_KEEPCNT support in setKeepAlive(). No security fixes were called out in the notable-changes list.
Why it matters: The virtual file system and package maps extend module-resolution and embedding options for tools and bundlers, and TLS certificate compression cuts handshake bytes for high-volume clients.
Follow-up: Track node:vfs and blockList (now release-candidate) toward stability and any backport of these features to the active LTS line.