c-ares up to 1.34.6 DNS Name Parsing ares_dns_name_parse resource consumption

Summaryinfo

A vulnerability described as problematic has been identified in c-ares up to 1.34.6. The impacted element is the function ares_dns_name_parse of the component DNS Name Parsing. Such manipulation leads to resource consumption. This vulnerability is listed as CVE-2026-69184. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in c-ares up to 1.34.6 and classified as problematic. Affected by this issue is the function ares_dns_name_parse of the component DNS Name Parsing. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. CVE summarizes:

c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_name_parse() enforces backward DNS compression pointers but does not bound the total pointer hops or assembled name length. A malicious DNS server can send a response containing a long descending pointer chain and many resource records whose NAME or RDATA fields refer to the chain, causing repeated decompression work that grows quadratically with message size. A single crafted response can stall the single-threaded c-ares event loop and deny DNS resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-69184 since 08/03/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 1.34.7 eliminates this vulnerability.

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Productinfo

Name

• c-ares

Version

• 1.34.0
• 1.34.1
• 1.34.2
• 1.34.3
• 1.34.4
• 1.34.5
• 1.34.6

Website

• Product: https://github.com/c-ares/c-ares/

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