{"id":"CVE-2026-42955","details":"In NLnet Labs Unbound 1.16.2 up to and including 1.25.1, a similar vulnerability as with CVE-2026-40622 in the 'ghost domain names' family of attacks was found in Unbound that could extend the ghost domain window by up to one cached TTL configured value for A/AAAA glue records. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client A/AAAA query can cause Unbound to overwrite the cached expired parent-side glue rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-referral-path: yes' is used (non-default configuration), no client query is required since Unbound implicitly performs that query. This is a variant of CVE-2026-40622 which only addressed the NS query.","modified":"2026-07-27T14:06:41.766697Z","published":"2026-07-22T14:17:18.680Z","related":["openSUSE-SU-2026:11380-1"],"references":[{"type":"ADVISORY","url":"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-42955.txt"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nlnetlabs/unbound","events":[{"introduced":"cbed768b8ff9bfcf11089a5f1699b7e5707f1ea5"},{"fixed":"c33ad1b1a21e48bfe4f140e90252a9be1b0c5745"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"1.16.2"},{"fixed":"1.25.2"}]}}],"versions":["release-1.25.1","release-1.25.0","release-1.25.0rc1","release-1.24.0","release-1.24.0rc1","release-1.23.0rc1","release-1.22.0","release-1.22.0rc1","release-1.21.0","release-1.21.0rc1","release-1.20.0rc1","release-1.20.0","release-1.19.3rc1","release-1.19.0rc1","release-1.19.0","release-1.18.0","release-1.18.0rc1","release-1.16.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42955.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}