CVE-2026-12245

Denial of DNS over TLS service by any DoT client

Published Jun 25, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
NSD from version 4.13.0 has a heap use-after-free bug in logging errors on TLS connections, causing a crash of the server process, which can be triggered trivially by sending a DNS query over a DoT connection, and closing the connection without reading the response.

Remediation

Vendor Solution

This issue is fixed starting with version 4.14.3.

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8474-1 NSD vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-617
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Important

Type Values Removed Values Added
First Time appeared Nlnetlabs
Nlnetlabs nsd
Vendors & Products Nlnetlabs
Nlnetlabs nsd
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description NSD from version 4.13.0 has a heap use-after-free bug in logging errors on TLS connections, causing a crash of the server process, which can be triggered trivially by sending a DNS query over a DoT connection, and closing the connection without reading the response.
Title Denial of DNS over TLS service by any DoT client
Weaknesses CWE-416
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
NLnet Labs
Published
Updated
Jun 25, 2026, 12:42 PM
Reserved
Jun 15, 2026, 6:47 AM
Status
Analyzed
Published
Jun 25, 2026, 7:16 AM
Modified
Oct 25, 2026, 11:10 PM
Severity
Important
Public date
Jun 25, 2026, 12:00 AM