CVE WatchJul 22, 2026

CVE-2026-42955

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 o

CVSS

3.7

Low

EPSS

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KEV

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Exploit Today

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0-100

Published: Jul 22, 2026 · Last modified: Jul 22, 2026 · CWE-672

EPSS · 30d

Not enough EPSS history yet.

Technical description

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.

Official references

www.nlnetlabs.nlhttps://www.nlnetlabs.nl/downloads/unbound/CVE-2026-42955.txt

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