CVE-2026-14586
MEDIUMDescription
In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, in DNS-over-QUIC environments, with high concurrency and under pressure, an assertion in libngtcp2 about monotonic timestamps could trigger and result in server termination and thus denial of service. When interfacing with libngtcp2, for DNS-over-QUIC support in Unbound, it is expected to use monotonic time. Unbound was using realtime instead, and in DoQ environments with high concurrency and under pressure, an assert in libngtcp2 for the quic timestamp would trigger and terminate the server.This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U
Exploit Intelligence
Low risk: more likely to be exploited than 19% of all known CVEs.
References
Related Vulnerabilities
Other CWE-617 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-8617 | High | 7.5 | 93% | - | Fix |
| CVE-2020-36222 | High | 7.5 | 78% | - | Fix |
| CVE-2006-5779 | High | 7.5 | 76% | - | Fix |
| CVE-2021-27212 | High | 7.5 | 64% | - | Fix |
| CVE-2018-5740 | High | 7.5 | 60% | - | Fix |
| CVE-2023-28425 | Medium | 5.5 | 55% | - | Fix |
Common questions
How do I fix CVE-2026-14586?
Published advisories record a fix for 3 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2026-14586 being actively exploited?
Not that we know of. CVE-2026-14586 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.27% is the estimated probability that it will be exploited in the next 30 days. That is higher than 19% of all scored CVEs.
How severe is CVE-2026-14586?
CVE-2026-14586 has a CVSS v3 base score of 5.9, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-14586 affect?
Published advisories record a fix for unbound (Debian), unbound (Red Hat / RHEL), unbound (Rocky). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-22.