CVE-2026-40622 Affecting unbound package, versions <0:1.16.2-5.12.el8_10


Severity

Recommended
0.0
high
0
10

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.14% (3rd percentile)

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  • Snyk IDSNYK-ALMALINUX8-UNBOUND-18511409
  • published3 Aug 2026
  • disclosed8 Jul 2026

Introduced: 8 Jul 2026

CVE-2026-40622  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:8 unbound to version 0:1.16.2-5.12.el8_10 or higher.
This issue was patched in ALSA-2026:37282.

NVD Description

Note: Versions mentioned in the description apply only to the upstream unbound package and not the unbound package as distributed by AlmaLinux. See How to fix? for AlmaLinux:8 relevant fixed versions and status.

NLnet 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.

CVSS Base Scores

version 3.1