CVE-2026-71851

crypto-js: Insufficient Entropy in Cryptographic Secret Generation via Vulnerable CryptoJS Dependency Chain

Published Aug 7, 2026 CVSS 3.1 · 9 Critical EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-rg76-677x-56q9 crypto-js: Insufficient Entropy in Cryptographic Secret Generation via Vulnerable CryptoJS Dependency Chain
History
Type Values Removed Values Added
First Time appeared Brix
Brix crypto-js
Vendors & Products Brix
Brix crypto-js
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title crypto-js: Insufficient Entropy in Cryptographic Secret Generation via Vulnerable CryptoJS Dependency Chain
Weaknesses CWE-331
CWE-334
CWE-338
References
Metrics cvssV3_1

{'score': 9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 8, 2026, 3:05 AM
Reserved
Aug 7, 2026, 6:26 PM
Status
Deferred
Published
Aug 7, 2026, 7:18 PM
Modified
Oct 24, 2026, 3:10 PM