CVE-2025-40905Network attack vectorHinoki check available

Predictable OAuth nonces via insecure rand entropy

Published Feb 12, 2026 · Updated Feb 12, 2026

Weak nonce generation in WWW::OAuth 1.000 and earlier allows remote attackers to predict OAuth request nonces used in signatures. The default oauth_nonce generator in lib/WWW/OAuth.pm derives its value with Perl's rand() instead of a cryptographically secure entropy source. Exposure requires an application to rely on default nonce generation; predictable nonces weaken request-signature replay protection.

CVSS severity7.3
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
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Summary

What happened

Weak nonce generation in WWW::OAuth 1.000 and earlier allows remote attackers to predict OAuth request nonces used in signatures. The default oauth_nonce generator in lib/WWW/OAuth.pm derives its value with Perl's rand() instead of a cryptographically secure entropy source. Exposure requires an application to rely on default nonce generation; predictable nonces weaken request-signature replay protection.

The record

CVE
CVE-2025-40905
Published
Feb 12, 2026
Updated
Feb 12, 2026
Vendor
Dan Book
Product
WWW::OAuth
Classifications
CWE-338
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 12, 2026Record 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=0 <=1.000

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Dan Book · WWW::OAuthversion=0 <=1.000

Published CVSS scores

7.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

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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