CVE-2026-35501 Affecting unbound-debuginfo package, versions <0:1.17.1-1.amzn2023.0.17


Severity

Recommended
medium

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.11% (2nd percentile)

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  • Snyk IDSNYK-AMZN2023-UNBOUNDDEBUGINFO-21705132
  • published25 Oct 2026
  • disclosed21 Oct 2026

Introduced: 21 Oct 2026

NewCVE-2026-35501  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 unbound-debuginfo to version 0:1.17.1-1.amzn2023.0.17 or higher.
This issue was patched in ALAS2023-2026-3313.

NVD Description

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

When NLnet Labs Unbound 1.0.1 up to and including version 1.26.1 is configured with both a root trust anchor and an additional 'trust-anchor:' for an island-of-security zone whose parent is provably insecure under the root chain, a malicious actor with a forged NSEC reply with the SOA bit cleared can trick Unbound to treat the configured trust island as insecure. This happens because the DNSSEC validator in Unbound accepts and caches the NSEC insecure response bypassing the RRSIG validation that the validator was supposed to do. The acceptance of the NSEC record at the trust anchor apex was allowed due to and old fix for type DS and NSEC queries from clients when trust anchor for that name existed.