CVE-2026-71851 crypto-js: Insufficient Entropy in Cryptographic Secret Generation via Vulnerable CryptoJS Dependency Chain
Insufficient entropy in crypto-js allows attackers to enumerate private keys and steal funds from downstream wallet applications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-71851?
CVE-2026-71851 is a critical vulnerability in brix crypto-js, published on 7 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
crypto-js is a JavaScript library of crypto standards. Versions of crypto-js prior to 4.0.0 generate randomness in CryptoJS.lib.WordArray.random() using a custom variation of the Multiply-With-Carry pseudorandom number generator, seeded from Math.random(), instead of a cryptographically secure source. This generator was introduced in version 3.1.2-4 and remained present in nearly every 3.x release. Nominal requests for 128 or 256 bits of entropy through this function produce effective search spaces of approximately 2 to the 39th and 2 to the 47th possibilities, small enough to enumerate on commodity hardware. Downstream wallet applications that used CryptoJS.lib.WordArray.random() as the entropy source for BIP39 recovery phrases are affected, and an attacker who enumerates the reduced output space can recover the resulting private keys and control the associated funds. This issue is fixed in version 4.0.0.
Which versions are affected by CVE-2026-71851?
2 open source packages ship an affected version, including crypto-js.
| Package | Affected | Fixed in |
|---|---|---|
crypto-js npm | All versions | 4.0.0 |
crypto-js npm | All versions | 4.0.0 |
How do I fix CVE-2026-71851?
Upgrade crypto-js to 4.0.0 or later.
Is CVE-2026-71851 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-71851 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as DEBIAN-CVE-2026-71851, GHSA-rg76-677x-56q9, ROOT-APP-NPM-CVE-2026-71851, UBUNTU-CVE-2026-71851.