Use-after-free in NSD - CVE-2026-12245
Published: June 25, 2026
Vulnerability identifier: #VU135155
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-12245
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: NLnet Labs
Affected software:
NSD
NSD
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to use-after-free in error logging on TLS connections when handling a DNS query over a DNS over TLS connection that is closed before the response is read. A remote attacker can send a DNS query over a DNS over TLS connection and close the connection early to cause a denial of service.
Only instances configured to use DNS over TLS are vulnerable.
How to mitigate CVE-2026-12245
Install security update from vendor's website.