Resource exhaustion in Nlnet Labs Unbound
CVE-2026-80225
In NLnetLabs Unbound up to and including 1.26.0, a degradation of service vulnerability is present in the TCP/DoT reading procedure where there is no limit on consecutive reads. A malicious actor that can stream and sustain a rate of distinct uncached names over the TCP/DoT connection, monopolizes a single worker's entire event loop for as long as its writes stay ahead of the drain.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
Affected products
Weakness classification (CWE)
References
- sep@nlnetlabs.nl (vendor-advisory)
Frequently asked questions
- What is CVE-2026-80225?
- CVE-2026-80225 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.3/10. Published 2026-09-16.
- How severe is CVE-2026-80225?
- Medium severity. CVSS v3 base score is 5.3 out of 10.