CVE-2026-40622 Detail
Awaiting Enrichment
This CVE record has been marked for NVD enrichment efforts. DescriptionNLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. 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 NS query can cause Unbound to overwrite the cached expired parent-side referral NS rrset with the child-side apex NS 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 NS query is required since Unbound implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension of TTLs for (parent) NS records regardless of their trust. Metrics
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CVSS 4.0 Severity and Vector Strings:
CNA: NLnet Labs
CVSS-BT 6.6 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Amber
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Weakness Enumeration
Quick InfoCVE Dictionary Entry:CVE-2026-40622 NVD Published Date: 05/20/2026 NVD Last Modified: 05/20/2026 Source: NLnet Labs |
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