UBUNTU-CVE-2026-33630
Dashboard / Vulnerabilities / UBUNTU-CVE-2026-33630
Summary:
Details: 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.
References: https://ubuntu.com/security/CVE-2026-33630, https://www.cve.org/CVERecord?id=CVE-2026-33630, https://www.openwall.com/lists/oss-security/2026/07/06/8, https://github.com/c-ares/c-ares/security/advisories/GHSA-6wfj-rwm7-3542
Affected packages
Package
Name: c-ares
Purl: pkg:deb/ubuntu/c-ares?arch=source&distro=esm-infra%2Fxenial
Affected ranges
Type: ECOSYSTEM
Events:
