What is CVE-2026-12245?

CVE-2026-12245 is a high-severity vulnerability in Nlnet Labs Nsd, classified under Use After Free. CVSS score: 7.5/10. Published 2026-06-25.

How severe is CVE-2026-12245?

High severity. CVSS v3 base score is 7.5 out of 10.

Use After Free in Nlnet Labs Nsd

CVE-2026-12245

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 wi…

Vulnerability class: Use-After-Free

EPSS: 0.003 (17.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Nlnet Labs Nsd — versions 4.13.0
Nlnetlabs Nsd

Weakness classification (CWE)

CWE-416 — Use After Free

References

sep@nlnetlabs.nl (vendor-advisory, Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-12245?: CVE-2026-12245 is a high-severity vulnerability in Nlnet Labs Nsd, classified under Use After Free. CVSS score: 7.5/10. Published 2026-06-25.
How severe is CVE-2026-12245?: High severity. CVSS v3 base score is 7.5 out of 10.