What’s Vulnerable › Vulnerabilities
CVE-2026-80225: Possible degradation of service from continuous queries on the same TCP/DoT connection
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-16 · updated 2026-09-23
- Weakness: CWE-770
Description
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.
Affected products
- NLnet Labs Unbound: before 1.26.1 — fixed in 1.26.1
How to fix
Upgrade to a fixed version: NLnet Labs Unbound 1.26.1. Check the vendor advisory for mitigations.
References
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