CVE-2026-41988

uuid before 14.0.0 can make unexpected writes when external output buffers are used, and the UUID version is 3, 5, or 6. In particular, UUID version 4, which is very commonly used, is unaffected by this issue.

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-w5hq-g745-h8pq. This link is maintained to preserve external references.

Original Advisory

uuid before 14.0.0 can make unexpected writes when external output buffers are used, and the UUID version is 3, 5, or 6. In particular, UUID version 4, which is very commonly used, is unaffected by this issue.

Summary

The v3(), v5(), and v6() API methods (not uuid release versions) accept external output buffers but do not reject out-of-range writes (small buf or large offset).
By contrast, v4(), v1(), and v7() API methods explicitly throw RangeError on invalid bounds.

This inconsistency allows silent partial writes into caller-provided buffers.

Affected code

• src/v35.ts (v3()/v5() path) writes buf[offset + i] without bounds validation.
• src/v6.ts writes buf[offset + i] without bounds validation.

Reproducible PoC

cd /home/StrawHat/uuid
npm ci
npm run build

node --input-type=module -e "
import {v4,v5,v6} from './dist-node/index.js';
const ns='6ba7b810-9dad-11d1-80b4-00c04fd430c8';
for (const [name,fn] of [
  ['v4()',()=>v4({},new Uint8Array(8),4)],
  ['v5()',()=>v5('x',ns,new Uint8Array(8),4)],
  ['v6()',()=>v6({},new Uint8Array(8),4)],
]) {
  try { fn(); console.log(name,'NO_THROW'); }
  catch(e){ console.log(name,'THREW',e.name); }
}"

Observed:

• v4() THREW RangeError
• v5() NO_THROW
• v6() NO_THROW

Example partial overwrite evidence captured during audit:

same true buf [
  170, 170, 170, 170,
   75, 224, 100,  63
]
v6 [
  187, 187, 187, 187,
   31,  19, 185,  64
]

Security impact

• Primary: integrity/robustness issue (silent partial output).
• If an application assumes full UUID writes into preallocated buffers, this can produce malformed/truncated/partially stale identifiers without error.
• In systems where caller-controlled offsets/buffer sizes are exposed indirectly, this may become a security-relevant logic flaw.

Suggested fix

Add the same guard used by v4()/v1()/v7():

if (offset < 0 || offset + 16 > buf.length) {
  throw new RangeError(`UUID byte range ${offset}:${offset + 15} is out of buffer bounds`);
}

Apply to:

• src/v35.ts (covers v3() and v5())
• src/v6.ts

uuid before 14.0.0 can make unexpected writes when external output buffers are used, and the UUID version is 3, 5, or 6. In particular, UUID version 4, which is very commonly used, is unaffected by this issue.