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CWE-331Weakness · CWE-331

CVE-2026-71851

CRITICAL · 9.0 CVSS v3.1 Published 2026-08-07
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
99/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available 2 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix High confidence

4.0.0

  1. Check current crypto-js version in project by running 'npm list crypto-js' or inspecting package.json
  2. Update package.json to specify crypto-js version 4.0.0 or later (e.g., "crypto-js": ">=4.0.0")
  3. Run 'npm install' or 'npm update' to install the fixed version
  4. Verify the installed version is 4.0.0 or higher using 'npm list crypto-js'
  5. Test the application thoroughly, particularly any functionality using WordArray.random() or BIP39 entropy generation
  6. If using BIP39 recovery phrases generated with vulnerable versions, consider migrating to newly generated phrases using the fixed library
Caveat Version 4.0.0 is a major version upgrade with API changes; review the crypto-js 4.0.0 changelog for breaking changes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-71851 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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