CVE intelligence

CVE-2023-31147

Vulnerability intelligence

Published May 25, 2023Sources checked Oct 29, 2026

6.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2023-31147 and is rated Medium severity with a CVSS score of 6.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 21, 2026

Vendor remediation details

CBL-Mariner Releases

Vendor-listed releases

1.62.0-2
1.19.1-1
21.1.2-3
18.17.1-2
16.20.1-2
1.42.0-10
2.1.10-1

CISA KEVNot listedBased on the latest collected catalog

EPSS0.9%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2023-31147?

c-ares is an asynchronous resolver library. When /dev/urandom or RtlGenRandom() are unavailable, c-ares uses rand() to generate random numbers used for DNS query ids.

This is not a CSPRNG, and it is also not seeded by srand() so will generate predictable output. Input from the random number generator is fed into a non-compilant RC4 implementation and may not be as strong as the original RC4 implementation.

No attempt is made to look for modern OS-provided CSPRNGs like arc4random() that is widely available. This issue has been fixed in version 1.19.1.

Source: NVD