CVE-2026-80225
Possible degradation of service from continuous queries on the same TCP/DoT connection
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.
INFO
Published Date :
Sept. 16, 2026, 9:17 a.m.
Last Modified :
Sept. 16, 2026, 7:41 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 206fc3a0-e175-490b-9eaa-a5738056c9f6 | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update NLnet Labs Unbound to version 1.27.0 or later.
- Monitor TCP/DoT connections for unusual activity.
- Limit consecutive reads on TCP/DoT connections.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-80225.
| URL | Resource |
|---|---|
| https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-80225.txt |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-80225 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-80225
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-80225 vulnerability anywhere in the article.
-
The Hacker News
Critical Unbound DNSSEC Validator Flaw Could Allow RCE via a Malicious DNS Zone
Every release of the Unbound DNS resolver before 1.26.1 has a critical heap overflow in its DNSSEC validator, maintainer NLnet Labs said in an advisory on Wednesday. An attacker who controls a malicio ... Read more
The following table lists the changes that have been made to the
CVE-2026-80225 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 16, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-80225', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-16T14:32:57.188145Z'} -
New CVE Received by [email protected]
Sep. 16, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-770 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80225.json">CVE-2026-80225</a> Added Reference https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-80225.txt