{"id":"ALPINE-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":"2026-09-18T17:30:02.299268463Z","published":"2026-07-22T14:17:18.680Z","upstream":["CVE-2026-42955"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2026-42955"}],"affected":[{"package":{"name":"unbound","ecosystem":"Alpine:v3.22","purl":"pkg:apk/alpine/unbound?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.16.2"},{"fixed":"1.25.2-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-42955.json"}},{"package":{"name":"unbound","ecosystem":"Alpine:v3.23","purl":"pkg:apk/alpine/unbound?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.16.2"},{"fixed":"1.25.2-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-42955.json"}},{"package":{"name":"unbound","ecosystem":"Alpine:v3.24","purl":"pkg:apk/alpine/unbound?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.16.2"},{"fixed":"1.25.2-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-42955.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}