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NVD / CVE Program· CNA mitre

CVE-2020-22217: Buffer overflow vulnerability in c-ares before 1_16_1 thru 1_17_0 via function ares_parse_soa_reply in ares_parse_soa_reply.c.

MediumCVSS 5.9 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 23/100)

  • 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: 0.97% (FIRST EPSS); higher than 62.5% 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. Special conditions such as timing or configuration are required.
  • Fixed version: c-ares (AlmaLinux:8) 1.13.0-9.el8_9.1; c-ares-devel (AlmaLinux:8) 1.13.0-9.el8_9.1; c-ares (Debian:10) 1.14.0-1+deb10u4.

Low priority for now. Upgrade to c-ares (AlmaLinux:8) 1.13.0-9.el8_9.1; c-ares-devel (AlmaLinux:8) 1.13.0-9.el8_9.1; c-ares (Debian:10) 1.14.0-1+deb10u4 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

Published
Aug 22, 2023
Updated
Jun 16, 2026
EPSS
0.9% · 62th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.9%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

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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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  • when exploit code appears or is weaponized
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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-aresc-ares
debiandebian linux

Affected versions

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

  • c-ares c-ares1.16.1
  • c-ares c-ares1.17.0
  • debian debian linux10.0

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8c-aresbefore 1.13.0-9.el8_9.11.13.0-9.el8_9.1
AlmaLinux:8c-ares-develbefore 1.13.0-9.el8_9.11.13.0-9.el8_9.1
Debian:10c-aresbefore 1.14.0-1+deb10u41.14.0-1+deb10u4
Debian:12c-aresbefore 1.17.1-11.17.1-1
Red Hat:enterprise_linux:8::baseosc-aresbefore 0:1.13.0-9.el8_9.10:1.13.0-9.el8_9.1
Red Hat:enterprise_linux:8::baseosc-ares-debuginfobefore 0:1.13.0-9.el8_9.10:1.13.0-9.el8_9.1
Red Hat:enterprise_linux:8::baseosc-ares-debugsourcebefore 0:1.13.0-9.el8_9.10:1.13.0-9.el8_9.1
Red Hat:enterprise_linux:8::baseosc-ares-develbefore 0:1.13.0-9.el8_9.10:1.13.0-9.el8_9.1
Red Hat:rhel_eus:8.6::baseosc-aresbefore 0:1.13.0-6.el8_6.30:1.13.0-6.el8_6.3
Red Hat:rhel_eus:8.6::baseosc-ares-debuginfobefore 0:1.13.0-6.el8_6.30:1.13.0-6.el8_6.3
Red Hat:rhel_eus:8.6::baseosc-ares-debugsourcebefore 0:1.13.0-6.el8_6.30:1.13.0-6.el8_6.3
Red Hat:rhel_eus:8.6::baseosc-ares-develbefore 0:1.13.0-6.el8_6.30:1.13.0-6.el8_6.3
Red Hat:rhel_eus:8.8::baseosc-aresbefore 0:1.13.0-6.el8_8.40:1.13.0-6.el8_8.4
Red Hat:rhel_eus:8.8::baseosc-ares-debuginfobefore 0:1.13.0-6.el8_8.40:1.13.0-6.el8_8.4
Red Hat:rhel_eus:8.8::baseosc-ares-debugsourcebefore 0:1.13.0-6.el8_8.40:1.13.0-6.el8_8.4
Red Hat:rhel_eus:8.8::baseosc-ares-develbefore 0:1.13.0-6.el8_8.40:1.13.0-6.el8_8.4
Rocky Linux:8c-aresbefore 0:1.13.0-9.el8_9.10:1.13.0-9.el8_9.1
SUSE:Linux Enterprise Software Development Kit 12 SP5libcares2before 1.9.1-9.18.11.9.1-9.18.1

Same product

c-ares: all records

Other highest-scoring records for the same primary product.

  • CVE-2016-5180Heap-based buffer overflow in the ares_create_query function in c-ares 1.x before 1.12.0 allows remote attackers to cause a denial of…
    42Plan
  • CVE-2025-31498c-ares has a use-after-free in read_answers()
    33Monitor
  • CVE-2017-1000381The c-ares function `ares_parse_naptr_reply()`, which is used for parsing NAPTR responses, could be triggered to read memory outside of the…
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2020-14354May 13, 2021 · A possible use-after-free and double-free in c-ares lib version 1.16.0 if ares_destroy() is called prior to ares_getaddrinfo() completing.
    13Monitor
  • Later →CVE-2024-25629Feb 23, 2024 · c-ares out of bounds read in ares__read_line()
    22Monitor
  • Later →CVE-2025-62408Dec 8, 2025 · c-ares has a Use After Free vulnerability when connection is cleaned up after error
    23Monitor

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
almalinux:c-ares1.13.0-9.el8_9.1 · AlmaLinux:8Package registry (OSV)
almalinux:c-ares-devel1.13.0-9.el8_9.1 · AlmaLinux:8Package registry (OSV)
debian:c-ares1.17.1-1 · Debian:12Package registry (OSV)
red hat:c-ares0:1.13.0-9.el8_9.1 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:c-ares-debuginfo0:1.13.0-9.el8_9.1 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:c-ares-debugsource0:1.13.0-9.el8_9.1 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:c-ares-devel0:1.13.0-9.el8_9.1 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
rocky linux:c-ares0:1.13.0-9.el8_9.1 · Rocky Linux:8Package registry (OSV)
suse:libcares21.9.1-9.18.1 · SUSE:Linux Enterprise Software Development Kit 12 SP5Package registry (OSV)

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.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

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.

ATT&CK techniques

—

References

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

All records