CVE-2026-12245: high-severity vulnerability in NLnet Labs NSD
Denial of DNS over TLS service by any DoT client
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.5%
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.
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
Affected products
NLnet Labs · NSDRelated CVEs — NLnet Labs NSD
In the same product, most dangerous first.
CVE-2020-28935—Local symlink attack in Unbound and NSDEPSS 0.5%CVE-2026-12244HIGHHeap overflow and crash with crafted SVCB RREPSS 0.5%CVE-2026-19401HIGHRemote UDP DoS by sending multiple DNS Cookie optionsEPSS 0.5%CVE-2026-18916MEDIUMRemote TCP DoS by throttling the TCP receive windowEPSS 0.5%CVE-2026-12246HIGHOut of bounds stack write with crafted APL RREPSS 0.4%CVE-2026-19538HIGHBypass of BLOCKED ACL items on proxy protocol port over TCP or TLSEPSS 0.4%