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


Severity

Recommended
0.0
high
0
10

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.14% (4th percentile)

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  • Snyk IDSNYK-ORACLE8-UNBOUNDLIBS-17939480
  • published10 Jul 2026
  • disclosed20 May 2026

Introduced: 20 May 2026

CVE-2026-40622  (opens in a new tab)

How to fix?

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

NVD Description

Note: Versions mentioned in the description apply only to the upstream unbound-libs package and not the unbound-libs package as distributed by Oracle. See How to fix? for Oracle: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