High 7.5Published Sep 3, 2026

CVE-2026-33630c-ares : Use-after-free / double-free in c-ares query-completion handling, remotely triggerable via ares_getaddrinfo() over TCP

Updated under an hour ago (Oct 26, 2026, 7:00 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

c-ares is an asynchronous resolver library. From ver 1.32.3 until 1.34.7, a use-after-free / double-free in c-ares' query-completion handling. The same flaw — a query's callback being invoked while the query is still linked in the channel's internal lookup structures — is present at multiple points in the resend/finish path (timeout handling, response handling, and query dispatch). If the query, or for ares_getaddrinfo() the owning host_query, is freed as a side effect of that callback, it is then accessed and/or freed a second time. This vulnerability is fixed in ver 1.34.7.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-415, CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Sep 4, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

c-ares c-ares c_ares:c_ares (from the name)	from 1.32.3, < 1.34.7	CNA record

References

References

https://github.com/c-ares/c-ares/security/advisories/GHSA-6wfj-rwm7-3542	x-refsource-confirm
https://github.com/c-ares/c-ares/pull/1237	x-refsource-misc
https://github.com/c-ares/c-ares/commit/1fa3b86a0b8d18fe7b60f3228a01d770feb026bc	x-refsource-misc
https://github.com/c-ares/c-ares/commit/d823199b688052dcdc1646f2ab4cb8c16b1c644a	x-refsource-misc
https://github.com/c-ares/c-ares/releases/tag/v1.34.7	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.