A flaw in Node.js crypto causes internal entropy caches used by randomUUID, randomUUIDv7, and randomInt to be written into user-land startup snapshots. When these functions (or dependent APIs such as URL.createObjectURL) are invoked while a snapshot is built, every process started from that snapshot emits the same values until the cache is refilled—up to 127 UUIDs and roughly 1,000 randomInt outputs. Identifiers that should be unique can collide across processes, and values produced by one process may be predicted by observing another, weakening confidentiality and potentially enabling targeted exploitation based on predictable IDs. The weakness is formally identified as CWE-330.

This vulnerability impacts Node.js 26.x, 24.x and 22.x. It affects any deployment that builds a startup snapshot with the --build-snapshot option or creates a single-executable application using the useSnapshot feature and invokes the affected crypto functions during snapshot creation.

With a CVSS score of 4.8 the flaw represents moderate severity. EPSS information is not available and the vulnerability is not listed in CISA KEV. Attacks are likely to be achieved by controlling or influencing snapshot generation, or by monitoring multiple processes that share the same cached entropy. An attacker who can trigger or observe the repeatable random values can force collisions or anticipate unique identifiers used in URLs, tokens, or other context-sensitive data. The impact is primarily non-RCE; the risk depends on whether an application’s correctness or security relies on the uniqueness of the affected random values.