CVE-2023-31147

low-risk

Published 2023-05-25

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.

Do I need to act?

0.09% chance of exploitation

EPSS score — low exploit probability

Not on CISA KEV list

No confirmed active exploitation reported to CISA

Patch status unknown

Check vendor advisories for fix availability and mitigation guidance

CVSS 5.9/10 Medium

NETWORK / HIGH complexity

Affected Products (3)

C-Ares

Fedora

Affected Vendors

Fedoraproject C-Ares Project

References (10)

Release Notes https://github.com/c-ares/c-ares/releases/tag/cares-1_19_1

Third Party Advisory https://github.com/c-ares/c-ares/security/advisories/GHSA-8r8p-23f3-64c2

Mailing List https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproje...

Third Party Advisory https://security.gentoo.org/glsa/202310-09

Release Notes https://github.com/c-ares/c-ares/releases/tag/cares-1_19_1

Third Party Advisory https://github.com/c-ares/c-ares/security/advisories/GHSA-8r8p-23f3-64c2

Mailing List https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproje...

Third Party Advisory https://security.gentoo.org/glsa/202310-09

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low-risk

Severity 18/34 · Moderate

Exploitability 0/34 · Minimal

Exposure 9/34 · Low