CVE-2015-8851Network attack vector

Guessable UUIDs via Math.random entropy fallback

Published Jan 30, 2020 · Updated Aug 6, 2024

Insufficient entropy in uuidjs uuid before 1.4.4 allows remote attackers to guess generated UUIDs through brute-force prediction. The Node.js entropy-selection path calls _global.require rather than require, catches the resulting failure, and selects its Math.random fallback. Exposure requires an application to use generated UUIDs as unpredictable secrets or object identifiers; the CVE record does not specify a downstream impact.

CVSS severity7.5
High
EPSS probability2.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient entropy in uuidjs uuid before 1.4.4 allows remote attackers to guess generated UUIDs through brute-force prediction. The Node.js entropy-selection path calls _global.require rather than require, catches the resulting failure, and selects its Math.random fallback. Exposure requires an application to use generated UUIDs as unpredictable secrets or object identifiers; the CVE record does not specify a downstream impact.

The record

CVE
CVE-2015-8851
Published
Jan 30, 2020
Updated
Aug 6, 2024
Vendor
uuidjs
Product
uuid
Classifications
CWE-331
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 30, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=before 1.4.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

uuidjs · uuidversion=before 1.4.4

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-331Insufficient Entropy

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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