CVE-2026-40622 Affecting unbound-utils-debuginfo package, versions <0:1.17.1-1.amzn2023.0.12


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.02% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-UNBOUNDUTILSDEBUGINFO-16887415
  • published27 May 2026
  • disclosed20 May 2026

Introduced: 20 May 2026

NewCVE-2026-40622  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 unbound-utils-debuginfo to version 0:1.17.1-1.amzn2023.0.12 or higher.
This issue was patched in ALAS2023-2026-1756.

NVD Description

Note: Versions mentioned in the description apply only to the upstream unbound-utils-debuginfo package and not the unbound-utils-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 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