CVE-2026-80225: CWE-770: Allocation of Resources Without Limits or Throttling in NLnet Labs Unbound
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.
AI Analysis
Technical Summary
CVE-2026-80225 is a resource exhaustion vulnerability in NLnet Labs Unbound (<=1.26.0) where the TCP/DoT reading procedure lacks limits on consecutive reads. An attacker capable of streaming a continuous flow of distinct uncached DNS queries over the TCP/DoT connection can monopolize a single worker's event loop, leading to service degradation. This is classified under CWE-770 (Allocation of Resources Without Limits or Throttling).
Potential Impact
The vulnerability results in a denial of service condition by degrading service availability. It does not affect confidentiality or integrity. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available in Unbound version 1.26.1 and later. Users should upgrade to version 1.26.1 or newer to remediate this vulnerability. No additional mitigation guidance is provided by the vendor advisory.
CVE-2026-80225: CWE-770: Allocation of Resources Without Limits or Throttling in NLnet Labs Unbound
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.
CVSS v3.1
Score 5.3medium
Affected software
NLnet Labs
Unbound
pkg:github/nlnetlabs/unboundRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-80225 is a resource exhaustion vulnerability in NLnet Labs Unbound (<=1.26.0) where the TCP/DoT reading procedure lacks limits on consecutive reads. An attacker capable of streaming a continuous flow of distinct uncached DNS queries over the TCP/DoT connection can monopolize a single worker's event loop, leading to service degradation. This is classified under CWE-770 (Allocation of Resources Without Limits or Throttling).
Potential Impact
The vulnerability results in a denial of service condition by degrading service availability. It does not affect confidentiality or integrity. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available in Unbound version 1.26.1 and later. Users should upgrade to version 1.26.1 or newer to remediate this vulnerability. No additional mitigation guidance is provided by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- NLnet Labs
- Date Reserved
- 2026-09-07T14:06:21.952Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aaa578955bf5e2cf540b1f9
Added to database: 09/16/2026, 08:47:05 UTC
Last enriched: 09/16/2026, 09:02:06 UTC
Last updated: 09/16/2026, 22:11:11 UTC
Views: 12
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