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CVE-2023-31147

21
FAUCET Score

CVE-2023-31147 is a medium-severity vulnerability affecting the c-ares asynchronous resolver library, as well as Fedora Project's c-ares and Fedora distributions. The flaw stems from insufficient randomness in generating DNS query identifiers when /dev/urandom or RtlGenRandom() are unavailable, leading to predictable output due to the use of a non-cryptographically secure pseudorandom number generator (rand()) and a non-compliant RC4 implementation. This vulnerability has a CVSS score of 6.5, indicating a network-based attack with low complexity that could result in limited confidentiality and integrity impacts. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or inclusion in the KEV catalog, though it has garnered some community discussion and media coverage. The issue has been patched in c-ares version 1.19.1.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.19.1CPE matchmatch criteria
cpe:2.3:a:c-ares_project:c-ares:*:*:*:*:*:*:*:*
37CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
38CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.9MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.91%
Probability of exploitation in next 30 days
EPSS Percentile
56.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0091 is in the 35th percentile among its peer group of 23,723 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (19)

microsoftpatch availablevia msrc
Product: cbl2 fluent-bit 2.1.10-1 on CBL Mariner 2.0Fixed in: 2.1.10-1
microsoftpatch availablevia msrc
Product: azl3 grpc 1.42.0-7 on Azure Linux 3.0Fixed in: 1.62.0-2
microsoftpatch availablevia msrc
Product: azl3 grpc 1.62.0-2 on Azure Linux 3.0Fixed in: 1.62.0-2
microsoftpatch availablevia msrc
Product: azl3 ceph 18.2.2-8 on Azure Linux 3.0Fixed in: 18.2.2-1
microsoftpatch availablevia msrc
Product: cm1 c-ares 1.19.1-1 on CBL Mariner 1.0Fixed in: 1.19.1-1
microsoftpatch availablevia msrc
Product: cbl2 c-ares 1.19.1-1 on CBL Mariner 2.0Fixed in: 1.19.1-1
microsoftpatch availablevia msrc
Product: cbl2 python-gevent 21.1.2-3 on CBL Mariner 2.0Fixed in: 21.1.2-3
microsoftpatch availablevia msrc
Product: cbl2 nodejs18 18.17.1-2 on CBL Mariner 2.0Fixed in: 18.17.1-2
microsoftpatch availablevia msrc
Product: cbl2 nodejs 16.20.1-2 on CBL Mariner 2.0Fixed in: 16.20.1-2
microsoftpatch availablevia msrc
Product: cbl2 grpc 1.42.0-10 on CBL Mariner 2.0Fixed in: 1.42.0-10
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: nodejs:16-8080020230608150024.63b34585
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Extended Update SupportFixed in: nodejs:16-8060020230620060944.ad008a3a
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: nodejs:18-9020020230531092345.rhel9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: nodejs-1:16.19.1-2.el9_2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: c-ares-0:1.19.1-1.el9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.0 Extended Update SupportFixed in: nodejs-1:16.18.1-4.el9_0
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-nodejs14-nodejs-0:14.21.3-4.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: nodejs:18-8080020230607122508.63b34585
View patch
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: c-ares

Vendor Advisories (2)

redhatCVE-2023-31147Moderate

c-ares: Insufficient randomness in generation of DNS query IDs

May 22, 2023
microsoft2023-May/CVE-2023-31147Moderate

Insufficient randomness in generation of DNS query IDs in c-ares

May 9, 2023

References

github.com / c-ares/c-ares/releases/tag/cares-1_19_1
Release Notes
github.com / c-ares/c-ares/security/advisories/GHSA-8r8p-23f3-64c2
Third Party Advisory
lists.fedoraproject.org / archives/list/[email protected]/message/B5Z5XFNXTNPTCBBVXFDNZQVLLIE6VRBY
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/[email protected]/message/UBFWILTA33LOSV23P44FGTQQIDRJHIY7
Mailing ListThird Party Advisory
security.gentoo.org / glsa/202310-09
Third Party Advisory