CVE-2023-31124Network attack vector

Predictable random values via unset entropy source

Published May 25, 2023 · Updated Feb 13, 2025

Insufficient randomness in c-ares before 1.19.1 allows remote attackers to predict security-sensitive values in Autotools cross-compiled builds. The Autotools configuration leaves CARES_RANDOM_FILE unset during cross-compilation, causing the library to fall back from a cryptographic source to rand(). Exploitation requires a build produced under that condition; the advisory does not identify a specific application-level consequence.

CVSS severity3.7
Low
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient randomness in c-ares before 1.19.1 allows remote attackers to predict security-sensitive values in Autotools cross-compiled builds. The Autotools configuration leaves CARES_RANDOM_FILE unset during cross-compilation, causing the library to fall back from a cryptographic source to rand(). Exploitation requires a build produced under that condition; the advisory does not identify a specific application-level consequence.

The record

CVE
CVE-2023-31124
Published
May 25, 2023
Updated
Feb 13, 2025
Vendor
c-ares Project
Product
c-ares
Classifications
CWE-330
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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=< 1.19.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

c-ares Project · c-aresversion=< 1.19.1

Published CVSS scores

3.7GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/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.

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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-330Use of Insufficiently Random Values

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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