CVE-2026-81642 NLnet Labs Unbound - Buffer Overflow

NLnet Labs Unbound <= 1.26.0 contains a buffer overflow in DNSSEC validator caused by a DNSKEY with an owner compression pointer to its own RDATA, letting remote attackers cause denial of service or remote code execution, exploit requires attacker-controlled malicious zone.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
Proof of concept available
Authentication
Not required
EPSS
0.96% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Buffer Overflow
Impact
Denial Of Service, Remote Code Execution
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
16 September 2026
Updated
15 October 2026
Weakness
CWE-122

Vendor fix

Update to the latest version beyond 1.26.0.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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