Improper Validation of Integrity Check Value Affecting unbound-debugsource package, versions <0:1.17.1-1.amzn2023.0.13


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.2% (11th percentile)

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  • Snyk IDSNYK-AMZN2023-UNBOUNDDEBUGSOURCE-18530790
  • published5 Aug 2026
  • disclosed22 Jul 2026

Introduced: 22 Jul 2026

NewCVE-2026-42955  (opens in a new tab)
CWE-354  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 unbound-debugsource to version 0:1.17.1-1.amzn2023.0.13 or higher.
This issue was patched in ALAS2023-2026-2033.

NVD Description

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

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.

CVSS Base Scores

version 3.1