{"id":"CVE-2026-33278","details":"NLnet Labs Unbound 1.19.1 up to and including version 1.25.0 has a vulnerability in the DNSSEC validator that enables denial of service and possible remote code execution as a result of deep copying a data structure and erroneously overwriting a destination pointer. An adversary can exploit the vulnerability by controlling a malicious signed zone and querying a vulnerable Unbound. When DS sub-queries need to suspend validation due to NSEC3 computational budget exhaustion (introduced in Unbound 1.19.1), Unbound deep-copies response messages to preserve them across memory region teardown. A struct-assignment bug overwrites the destination's pointer with the source's pointer. After the sub-query region is freed, the resumed validator dereferences this dangling pointer, triggering a crash or potentially enabling arbitrary code execution. Unbound 1.25.1 contains a patch with a fix to preserve the correct pointer when deep copying the data structure.","modified":"2026-07-08T07:32:33.158278689Z","published":"2026-05-20T10:16:26.530Z","related":["ALSA-2026:23231","ALSA-2026:24369","SUSE-SU-2026:21874-1","SUSE-SU-2026:21913-1","SUSE-SU-2026:22160-1","SUSE-SU-2026:22213-1","SUSE-SU-2026:2281-1","SUSE-SU-2026:2369-1","openSUSE-SU-2026:10903-1","openSUSE-SU-2026:21083-1"],"database_specific":{},"references":[{"type":"WEB","url":"https://access.redhat.com/security/cve/CVE-2026-33278"},{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33278.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:19752"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:23231"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:24369"},{"type":"ADVISORY","url":"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-33278.txt"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2479808"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nlnetlabs/unbound","events":[{"introduced":"c6dd1e116df75242a0c032295c152f06c721b3cd"},{"fixed":"75b6dba593d4fff000434cd64807c6ebd50bd244"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"1.19.1"},{"fixed":"1.25.1"}]}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33278.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}