Double Free Affecting c-ares package, versions <1.34.5-1+deb13u1+e1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.84% (57th percentile)

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  • Snyk IDSNYK-ECHOLATEST-CARES-19643599
  • published8 Sept 2026
  • disclosed3 Sept 2026

Introduced: 3 Sep 2026

CVE-2026-33630  (opens in a new tab)
CWE-415  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade Echo:latest c-ares to version 1.34.5-1+deb13u1+e1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream c-ares package and not the c-ares package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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 Base Scores

version 3.1