CVE-2026-12245: Denial of DNS over TLS service by any DoT client

Published Jun 25, 2026
·
Updated

Last updated 29 June 2026

Other sources

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.

— NVD

Affected Software

3 affected componentsFixes available
Nlnet Labs NSD>=undefined
nlnetlabs Nsd>=4.13.0<4.14.3
debian/nsd
4.3.5-14.6.1-14.12.0-14.14.3-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade debian/nsd to a version that resolves this vulnerability.

    Fixed in 4.3.5-1Fixed in 4.6.1-1Fixed in 4.12.0-1Fixed in 4.14.3-1
  2. Upgrade

    Upgrade nsd to a version that resolves this vulnerability.

    Fixed in 4.14.3

Event History

Jun 25, 2026
CVE Published
via MITRE·05:24 AM
Data Sourced
via MITRE·05:24 AM
RemedyDescriptionWeakness
Data Sourced
via NVD·07:16 AM
RemedyDescriptionSeverityWeaknessAffected Software
Jun 28, 2026
Data Sourced
via Debian·04:29 PM
DescriptionAffected Software
Jun 29, 2026
Data Sourced
via Ubuntu·04:29 PM
RemedyDescriptionSeverityAffected Software
Jun 30, 2026
Data Sourced
via Launchpad·04:32 PM
Description
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Frequently Asked Questions

1

What is the severity of CVE-2026-12245?

CVE-2026-12245 has a high severity rating of 8.7.

2

How do I fix CVE-2026-12245?

To fix CVE-2026-12245, update your NSD software to version 4.13.1 or later.

3

What type of vulnerability is CVE-2026-12245?

CVE-2026-12245 is a heap use-after-free vulnerability that affects DNS over TLS services.

4

What impact does CVE-2026-12245 have on my system?

CVE-2026-12245 can cause a denial of service by crashing the NSD server process.

5

Who is affected by CVE-2026-12245?

Any users running NSD version 4.13.0 are affected by CVE-2026-12245.

Company

Resources

Contact

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