CVE-2025-2814

Predictable cryptographic values via rand fallback

Published Apr 12, 2025 · Updated Sep 5, 2025

Insufficient entropy in Lincoln Stein Crypt::CBC 1.21 through 3.05 allows attackers to predict values used during encryption. The _get_random_bytes routine reads /dev/urandom when available but otherwise fills requested bytes with repeated Perl rand() calls. The flaw is reached only when that device is unreadable, producing insufficiently random salts or initialization vectors.

CVSS severity4.0
Medium
EPSS probability0.20%
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 Lincoln Stein Crypt::CBC 1.21 through 3.05 allows attackers to predict values used during encryption. The _get_random_bytes routine reads /dev/urandom when available but otherwise fills requested bytes with repeated Perl rand() calls. The flaw is reached only when that device is unreadable, producing insufficiently random salts or initialization vectors.

The record

CVE
CVE-2025-2814
Published
Apr 12, 2025
Updated
Sep 5, 2025
Vendor
Lincoln Stein
Product
Crypt::CBC
Classifications
CWE-331, CWE-338, CWE-329
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 2025Record 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=1.21 <=3.05

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Lincoln Stein · Crypt::CBCversion=1.21 <=3.05

Published CVSS scores

4.0CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-331Insufficient Entropy
CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
CWE-329Generation of Predictable IV with CBC Mode

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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