Vulnerability 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.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/brix/crypto-js/commit/b405ff597fb3ac76a7bdfbc72dca10ba1079b1d
- https://github.com/brix/crypto-js/security/advisories/GHSA-rg76-677x-56q9
- https://www.coinspect.com/blog/ill-bloom-investigation
- https://github.com/brix/crypto-js/security/advisories/GHSA-rg76-677x-56q9
FAQ
What is CVE-2026-71851?
CVE-2026-71851 is a vulnerability with a CVSS score of 9.0 (CRITICAL). 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 p...
How severe is CVE-2026-71851?
CVE-2026-71851 has been rated CRITICAL with a CVSS base score of 9.0/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-71851?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.