CVE-2023-31147

Name: CVE-2023-31147
Creator: NVD / NIST
Published: 2023-05-25T22:15:09.833+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.91%

Last modified Jun 17, 2026

CVE-2023-31147 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.91% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

0.91%

55.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
C-Ares Project	C-Ares	< 1.19.1
Fedoraproject	Fedora	37
Fedoraproject	Fedora	38

References

https://github.com/c-ares/c-ares/releases/tag/cares-1_19_1Release Notes
https://github.com/c-ares/c-ares/security/advisories/GHSA-8r8p-23f3-64c2Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/B5Z5XFNXTNPTCBBVXFDNZQVLLIE6VRBY/Mailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UBFWILTA33LOSV23P44FGTQQIDRJHIY7/Mailing List, Third Party Advisory
https://security.gentoo.org/glsa/202310-09Third Party Advisory
https://github.com/c-ares/c-ares/releases/tag/cares-1_19_1Release Notes
https://github.com/c-ares/c-ares/security/advisories/GHSA-8r8p-23f3-64c2Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/B5Z5XFNXTNPTCBBVXFDNZQVLLIE6VRBY/Mailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UBFWILTA33LOSV23P44FGTQQIDRJHIY7/Mailing List, Third Party Advisory
https://security.gentoo.org/glsa/202310-09Third Party Advisory

Timeline

Published: May 25, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-31147?

How severe is CVE-2023-31147?

CVE-2023-31147 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.91% probability of exploitation in the next 30 days.

How do I fix CVE-2023-31147?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-31147?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST