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CVE-2026-81642

9.8 CRITICAL

Published 2026-09-16 · Updated 2026-09-22

AI risk analysis

Summary
The vulnerability in Unbound allows remote attackers to cause a denial of service or execute arbitrary code by manipulating DNSKEYs, which can overflow the digest buffer.
Exploitability
Exploitation requires control over a malicious zone and querying a vulnerable Unbound instance; this is moderately difficult due to the need for precise DNSKEY manipulation.
Blast radius
If exploited, the impact could be severe, leading to service disruption or remote code execution on affected systems.
Prioritized remediation
Upgrade to Unbound version 1.27.0 or later, which includes a fix for this vulnerability.
rcedosdnsunbound

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD 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 vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

CWE-122

Vendors

nlnetlabs

Products

unbound

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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