CVE-2026-106074: Node.js crypto.randomUUID() and randomInt() entropy caches are saved into user-land startup snapshots and SEAs

To make crypto.randomUUID() and crypto.randomInt() fast, Node.js fills a small cache of random bytes ahead of time and hands values out from it. A startup snapshot captures the JavaScript heap after your setup code runs, so processes start faster. If that setup code called randomUUID() or randomInt() even once, the partly used cache went into the snapshot. Every process deserialized from it started with the same leftover bytes and returned the same sequence of values until the cache ran out.

In practice, values that should be unique and unguessable repeat across machines and restarts: request IDs, idempotency keys, session or invitation tokens, temporary file names, or random choices used for security. An attacker who obtains one copy of the SEA binary or snapshot, or who observes the first values from one instance, can predict the values other instances will produce. Collisions also break logic that assumes UUIDs are unique. The fix clears the caches after user serialization callbacks and before user deserialization callbacks, which also covers caches refilled by microtasks, next ticks or exit handlers.

Affected: Node.js 22.x before 22.23.4, 24.x before 24.22.1 and 26.x before 26.12.1, but only for processes started from a user-land startup snapshot (built with --build-snapshot or the node:v8 startupSnapshot API) or an SEA built with a snapshot. Plain node app.js is not affected. To check:

node -v
grep -rn "build-snapshot\|startupSnapshot\|useSnapshot" --include=*.json --include=*.js --include=*.mjs .

The SEA configuration file shows useSnapshot when a snapshot is embedded.

Upgrade the build toolchain to Node.js 22.23.4, 24.22.1 or 26.12.1, then rebuild every snapshot blob and every SEA binary. Upgrading the runtime alone does not fix an SEA, because the snapshot is baked into the file you ship.

After rebuilding, rotate anything security-relevant that affected binaries generated with randomUUID() or randomInt() early in their life, such as long-lived tokens or keys.

Look for duplicate UUIDs or random IDs across instances in logs and databases, especially among the first values each process produced after start. Unique-constraint violations on UUID columns after deploys of an SEA build are a strong sign. Comparing the first few request IDs from two freshly started instances shows the problem directly.

Node.js keeps caches of pre-generated random data for crypto.randomUUID() and crypto.randomInt(). Unused cache entries were saved into user-land startup snapshots and single executable applications, so every process started from the same snapshot replayed the same random values. The fix clears the caches around snapshot serialization and deserialization. Affected: Node.js 22.x before 22.23.4, 24.x before 24.22.1 and 26.x before 26.12.1. Fixed in Node.js 22.23.4, 24.22.1 and 26.12.1, released October 21, 2026.