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NVD / CVE Program· CNA GitHub_M

CVE-2023-31147: Insufficient randomness in generation of DNS query IDs in c-ares

MediumCVSS 6.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.90% (FIRST EPSS); higher than 60.2% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: c-ares c-ares 1.19.1; azl3 grpc 1.42.0-7 on Azure Linux 3.0 1.62.0-2; azl3 grpc 1.62.0-2 on Azure Linux 3.0 1.62.0-2.

Low priority for now. Upgrade to c-ares c-ares 1.19.1; azl3 grpc 1.42.0-7 on Azure Linux 3.0 1.62.0-2; azl3 grpc 1.62.0-2 on Azure Linux 3.0 1.62.0-2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
May 25, 2023
Updated
Jun 17, 2026
EPSS
0.9% · 60th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.9%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.5
CNA · GitHub_M
5.9
0.6 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Follow CVE-2023-31147

When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
c-ares projectc-ares
fedoraprojectfedora

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • c-ares c-ares

    • < 1.19.1affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • c-ares project c-aresbefore 1.19.1
  • fedoraproject fedora37
  • fedoraproject fedora38

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8nodejsbefore 1:16.19.1-2.module_el8.8.0+3586+d4fc0b721:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8nodejsbefore 1:18.14.2-3.module_el8.8.0+3587+ee6522441:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8nodejs-develbefore 1:18.14.2-3.module_el8.8.0+3587+ee6522441:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8nodejs-develbefore 1:16.19.1-2.module_el8.8.0+3586+d4fc0b721:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8nodejs-docsbefore 1:18.14.2-3.module_el8.8.0+3587+ee6522441:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8nodejs-docsbefore 1:16.19.1-2.module_el8.8.0+3586+d4fc0b721:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8nodejs-full-i18nbefore 1:16.19.1-2.module_el8.8.0+3586+d4fc0b721:16.19.1-2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8nodejs-full-i18nbefore 1:18.14.2-3.module_el8.8.0+3587+ee6522441:18.14.2-3.module_el8.8.0+3587+ee652244
AlmaLinux:8nodejs-nodemonbefore 2.0.20-2.module_el8.8.0+3587+ee6522442.0.20-2.module_el8.8.0+3587+ee652244
AlmaLinux:8nodejs-nodemonbefore 2.0.20-3.module_el8.8.0+3586+d4fc0b722.0.20-3.module_el8.8.0+3586+d4fc0b72
AlmaLinux:8nodejs-packagingbefore 25-1.module_el8.5.0+2605+45d748af25-1.module_el8.5.0+2605+45d748af
AlmaLinux:8nodejs-packagingbefore 2021.06-4.module_el8.7.0+3343+ea2b79012021.06-4.module_el8.7.0+3343+ea2b7901
AlmaLinux:8nodejs-packaging-bundlerbefore 2021.06-4.module_el8.7.0+3343+ea2b79012021.06-4.module_el8.7.0+3343+ea2b7901
AlmaLinux:8npmbefore 1:9.5.0-1.18.14.2.3.module_el8.8.0+3587+ee6522441:9.5.0-1.18.14.2.3.module_el8.8.0+3587+ee652244
AlmaLinux:8npmbefore 1:8.19.3-1.16.19.1.2.module_el8.8.0+3586+d4fc0b721:8.19.3-1.16.19.1.2.module_el8.8.0+3586+d4fc0b72
AlmaLinux:9c-aresbefore 1.19.1-1.el91.19.1-1.el9
AlmaLinux:9c-ares-develbefore 1.19.1-1.el91.19.1-1.el9
AlmaLinux:9nodejsbefore 1:16.19.1-2.el9_21:16.19.1-2.el9_2
AlmaLinux:9nodejsbefore 1:18.14.2-3.module_el9.2.0+30+e33124931:18.14.2-3.module_el9.2.0+30+e3312493
AlmaLinux:9nodejs-develbefore 1:18.14.2-3.module_el9.2.0+30+e33124931:18.14.2-3.module_el9.2.0+30+e3312493
AlmaLinux:9nodejs-docsbefore 1:18.14.2-3.module_el9.2.0+30+e33124931:18.14.2-3.module_el9.2.0+30+e3312493
AlmaLinux:9nodejs-docsbefore 1:16.19.1-2.el9_21:16.19.1-2.el9_2
AlmaLinux:9nodejs-full-i18nbefore 1:18.14.2-3.module_el9.2.0+30+e33124931:18.14.2-3.module_el9.2.0+30+e3312493
AlmaLinux:9nodejs-full-i18nbefore 1:16.19.1-2.el9_21:16.19.1-2.el9_2

+96

Same product

c-ares project: all records

Other highest-scoring records for the same primary product.

Published before and after this one in the same product

  • ← EarlierCVE-2021-3672Nov 23, 2021 · A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to…
    23Monitor
  • ← EarlierCVE-2023-31124May 25, 2023 · AutoTools does not set CARES_RANDOM_FILE during cross compilation
    14Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
c-ares c-ares1.19.1 · descriptionVendor (CNA)
azl3 grpc 1.42.0-7 on Azure Linux 3.01.62.0-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 grpc 1.62.0-2 on Azure Linux 3.01.62.0-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 c-ares 1.19.1-1 on CBL Mariner 2.01.19.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 fluent-bit 2.1.10-1 on CBL Mariner 2.02.1.10-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 grpc 1.42.0-10 on CBL Mariner 2.01.42.0-10 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 nodejs 16.20.1-2 on CBL Mariner 2.016.20.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 nodejs18 18.17.1-2 on CBL Mariner 2.018.17.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 python-gevent 21.1.2-3 on CBL Mariner 2.021.1.2-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
cm1 c-ares 1.19.1-1 on CBL Mariner 1.01.19.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:c-ares1.19.1-1.el9 · AlmaLinux:9Package registry (OSV)
almalinux:c-ares-devel1.19.1-1.el9 · AlmaLinux:9Package registry (OSV)
almalinux:nodejs1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9Package registry (OSV)
almalinux:nodejs-devel1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9Package registry (OSV)
almalinux:nodejs-docs1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9Package registry (OSV)
almalinux:nodejs-full-i18n1:18.14.2-3.module_el9.2.0+30+e3312493 · AlmaLinux:9Package registry (OSV)
almalinux:nodejs-libs1:16.19.1-2.el9_2 · AlmaLinux:9Package registry (OSV)
almalinux:nodejs-nodemon2.0.20-2.module_el9.2.0+29+de583a0b · AlmaLinux:9Package registry (OSV)
almalinux:nodejs-packaging2021.06-4.module_el9.1.0+13+d9a595ea · AlmaLinux:9Package registry (OSV)
almalinux:nodejs-packaging-bundler2021.06-4.module_el9.1.0+13+d9a595ea · AlmaLinux:9Package registry (OSV)
almalinux:npm1:9.5.0-1.18.14.2.3.module_el9.2.0+30+e3312493 · AlmaLinux:9Package registry (OSV)
debian:c-ares1.19.1-2 · Debian:13Package registry (OSV)
opensuse:c-ares1.19.1-150000.3.23.1 · openSUSE:Leap Micro 5.3Package registry (OSV)
opensuse:nodejs1616.20.1-150400.3.21.1 · openSUSE:Leap 15.4Package registry (OSV)
opensuse:nodejs1818.16.1-150400.9.9.1 · openSUSE:Leap 15.4Package registry (OSV)
red hat:nodejs1:18.14.2-3.module+el9.2.0.z+18964+42696395 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:nodejs-debuginfo1:18.14.2-3.module+el9.2.0.z+18964+42696395 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:nodejs-debugsource1:18.14.2-3.module+el9.2.0.z+18964+42696395 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:nodejs-devel1:18.14.2-3.module+el9.2.0.z+18964+42696395 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:nodejs-docs1:18.14.2-3.module+el9.2.0.z+18964+42696395 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)

+16

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-330 · Use of Insufficiently Random Values

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records