CVE-2026-71851
CriticalCVSS 9.0Summary
crypto-js prior to version 4.0.0 generates 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 in nearly every 3.x release. Requests for 128 or 256 bits of entropy produce effective search spaces of approximately 2^39 and 2^47 possibilities, small enough to enumerate on commodity hardware.
Risk Assessment
Wallet applications using CryptoJS.lib.WordArray.random() as the entropy source for BIP39 recovery phrases are vulnerable to an attacker who can enumerate the reduced output space and recover private keys, controlling associated funds.
Recommendation
Upgrade crypto-js to version 4.0.0 or later, which includes the fix.
Original NVD description (English source)
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.