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VulnerabilityPublished

CVE-2026-109125: unbound security update

Affects unboundSource GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-109125· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.17.1-25.oe2403sp3 when convenient.

Data as of 4 Nov 2026, 16:47 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (NLnet Labs)CVSS 3.15.3
Patch
Available – fixed in 1.17.1-25.oe2403sp3
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 21 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.

What to do

Upgrade unbound to 1.17.1-25.oe2403sp3.

Affected software

ProductAffectedFixed in
openEuler 24.03-LTS-SP3unboundpkg:rpm/openEuler/unbound&distro=openEuler-24.03-LTS-SP3Other threatsAffected
  • <1.17.1-25.oe2403sp3
Fixed in
  • 1.17.1-25.oe2403sp3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available in Unbound version 1.17.1-25.oe2403sp3 that addresses these vulnerabilities. Users should upgrade to this fixed version to mitigate the described issues. Since the cache side-channel attack requires non-default configuration, reviewing and avoiding 'unwanted-reply-threshold' settings greater than zero can reduce risk until patched. No other specific mitigations are indicated by the vendor advisory.

Description

NLnet Labs Unbound up to and including version 1.26.1 contains multiple vulnerabilities including a cache-level side-channel that can be exploited under specific non-default configurations, DNSSEC validation bypasses in certain trust-anchor configurations, and a denial-of-service condition via excessive compression pointer traversal. These issues can lead to cache poisoning, incorrect DNSSEC validation resulting in insecure treatment of zones, and performance degradation. A fix is available in version 1.17.1-25.oe2403sp3.

References

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