CVE-2026-69186

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.
Configurations

No configuration.

History

18 Sep 2026, 20:17

Type Values Removed Values Added
References () https://github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj - () https://github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj -

18 Sep 2026, 18:17

Type Values Removed Values Added
New CVE

Information

Published : 2026-09-18 18:17

Updated : 2026-09-23 18:12


NVD link : CVE-2026-69186

Mitre link : CVE-2026-69186

CVE.ORG link : CVE-2026-69186


JSON object : View

Products Affected

No product.

CWE
CWE-400

Uncontrolled Resource Consumption