Read the docs
TI-2026-29354 Aliases CVE-2026-40622GHSA-m3vq-fgh9-hq65

Another 'ghost domain names' attack variant

Priority LOW 34CWE-346Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
None · High · None
Fix status
Partial Red Hat: 7 fixed, 4 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-346.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00142 3rd percentileScored 2026-11-07
Fix Partial Unbound (NLnet Labs): 1.25.1Red Hat: 5 advisoriesRed Hat: 7 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
NLnet LabsUnbound1.16.2 to before 1.25.11.25.1Patch availableCNA
  • Unbound VendorNLnet Labs Affected 1.16.2 to before 1.25.1 Fixed in 1.25.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*1.16.2 to before 1.25.1VulnerableNLNETLABS
  • cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:* Versions 1.16.2 to before 1.25.1 Vulnerable ·NLNETLABS

Remediation

  • Fix · CNA Unbound (NLnet Labs) Fixed in 1.25.1

Red Hat 5 advisories

  • RHSA-2026:54769 Released 2026-08-18 · Red Hat rating Important
    OpenShift Container Platform 4.22.10 bug fix and security update
    • Red Hat OpenShift Container Platform 4.22 rhcos-aarch64-4.22.9.8.202608130832-0, rhcos-ppc64le-4.22.9.8.202608130832-0, rhcos-s390x-4.22.9.8.202608130832-0 +1
  • RHSA-2026:37282 Released 2026-07-09 · Red Hat rating Important
    unbound security update
    • Red Hat Enterprise Linux AppStream (v. 8) python3-unbound-1.16.2-5.12.el8_10, unbound-1.16.2-5.12.el8_10, unbound-devel-1.16.2-5.12.el8_10 +1
  • RHSA-2026:36777 Released 2026-07-08 · Red Hat rating Important
    unbound security update
    • Red Hat Enterprise Linux AppStream (v. 9) python3-unbound-1.24.2-3.el9_8.2, unbound-1.24.2-3.el9_8.2, unbound-dracut-1.24.2-3.el9_8.2 +1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) unbound-devel-1.24.2-3.el9_8.2
Show 2 more Red Hat advisories
  • RHSA-2026:36320 Released 2026-07-07 · Red Hat rating Important
    unbound security update
    • Red Hat Enterprise Linux AppStream (v. 10) python3-unbound-1.24.2-7.el10_2.2, unbound-1.24.2-7.el10_2.2, unbound-anchor-1.24.2-7.el10_2.2 +3
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) unbound-devel-1.24.2-7.el10_2.2
  • RHSA-2026:20357 Released 2026-05-23 · Red Hat rating Moderate
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images python3-unbound-1.25.1-1.hum1@aarch64, python3-unbound-1.25.1-1.hum1@x86_64, unbound-1.25.1-1.hum1@aarch64 +14

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    NLnet Labs Unbound 1.25.1

    11 records Highest priority Priority MEDIUM 3 MEDIUM, 8 LOW

    Other records, highest priority first

    • TI-2026-25690 Possible arbitrary code execution during DNSSEC validationPriority MEDIUM 50
    • TI-2026-31146 Crash during DNSSEC validation of malicious contentPriority MEDIUM 45
    • TI-2026-31135 Heap overflow with multiple NSID, COOKIE, PADDING EDNS optionsPriority MEDIUM 45
    Show all 11 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet
Red Hat OpenShift Container Platform 4AffectedNo fix yet
Red Hat OpenShift Container Platform 5AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:36320
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:37282
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:36777
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:36320
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:36777
Red Hat Hardened ImagesFixed RHSA-2026:20357
Red Hat OpenShift Container Platform 4.22Fixed RHSA-2026:54769

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-40622
  2. 2026-10-03 Alias added: GHSA-m3vq-fgh9-hq65
  3. 2026-11-06 Affected versions changed · Red Hat

References

Patch 1

  • TI-2026-25690 Possible arbitrary code execution during DNSSEC validation CVSS 4.0CRITICAL 9.1
  • TI-2026-56302 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY CVSS 4.0CRITICAL 9.1
  • TI-2026-31146 Crash during DNSSEC validation of malicious content CVSS 4.0HIGH 8.7
  • TI-2026-31135 Heap overflow with multiple NSID, COOKIE, PADDING EDNS options CVSS 4.0HIGH 8.7
  • TI-2026-36436 Routinator crashes on specifically crafted RRDP XML files CVSS 4.0HIGH 8.7
  • TI-2026-36433 Routinator exits when accepting an incoming HTTP or RTR connection fails CVSS 4.0HIGH 8.7
See all 96 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences