CVE-2026-69186
mediumc-ares is an asynchronous resolver library.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://github.com/c-ares/c-ares/commit/e47c203f91cd8b749c8736bc18d75a31ffdec8f4 security-advisories@github.com
- https://github.com/c-ares/c-ares/commit/eaded4cb200b2a5f8d73f11021ff7c8d6968aaab security-advisories@github.com
- https://github.com/c-ares/c-ares/pull/1134 security-advisories@github.com
- https://github.com/c-ares/c-ares/releases/tag/v1.34.7 security-advisories@github.com
- https://github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj security-advisories@github.com
- https://github.com/c-ares/c-ares/security/advisories/GHSA-jv8r-gqr9-68wj 134c704f-9b21-4f2e-91b3-4a467353bcc0