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CVE-2026-81642

Nlnetlabs Unbound remote code execution

9.8 CRITICALEPSS 0.96%
  1. Published16 Sept 2026

Description

In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Nlnetlabs Unbound< 1.26.1

Remediation

Fixed in
Nlnetlabs Unbound≥ 1.26.1

References

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Frequently asked

Is CVE-2026-81642 being actively exploited?

CVE-2026-81642 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.96%.

How severe is CVE-2026-81642?

CVE-2026-81642 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.96% probability of exploitation.

Which products are affected by CVE-2026-81642?

Affected products include Nlnetlabs Unbound.

How do I fix CVE-2026-81642?

Upgrade affected software to a fixed version, for example Nlnetlabs Unbound 1.26.1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-81642 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.