---
id: CVE-2026-69186
title: c-ares is an asynchronous resolver library
summary: >-
  c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_parse()
  trusts the attacker-controlled ANCOUNT, NSCOUNT, and ARCOUNT fields before
  confirming that the DNS response contains enough bytes for the claimed
  records. Beca…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-400
  - CWE-1284
vendor: c-ares
product: c-ares
affected:
  - c-ares < 1.34.7
published: '2026-09-18'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T18:12:04.247'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-69186'
references:
  - url: >-
      https://github.com/c-ares/c-ares/commit/e47c203f91cd8b749c8736bc18d75a31ffdec8f4
    label: security-advisories@github.com
  - url: >-
      https://github.com/c-ares/c-ares/commit/eaded4cb200b2a5f8d73f11021ff7c8d6968aaab
    label: security-advisories@github.com
  - url: 'https://github.com/c-ares/c-ares/pull/1134'
    label: security-advisories@github.com
  - url: 'https://github.com/c-ares/c-ares/releases/tag/v1.34.7'
    label: security-advisories@github.com
  - url: 'https://github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj'
    label: security-advisories@github.com
  - url: 'https://github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-69186.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-69186'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2538212'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-69186'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-69186'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00524
epssPercentile: 0.41913
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-18T19:50:58.245833Z'
ingestedAt: '2026-09-18T17:46:41.540Z'
scores:
  nvd: 5.3
  vendor: 7.5
---

## Overview

c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_parse() trusts the attacker-controlled ANCOUNT, NSCOUNT, and ARCOUNT fields before confirming that the DNS response contains enough bytes for the claimed records. Because process_answer() invokes parsing before transaction ID and question validation, a malicious DNS response can cause ares_dns_record_rr_prealloc() and ares_array_set_size() to reserve disproportionate heap memory for a tiny message. Repeated responses create large allocation and release cycles that can degrade or deny name resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Hardened Images, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Hardened Images, Red Hat OpenShift Container Platform 4 · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-69186.json)