Improper access control in NSD - CVE-2026-12490
Published: June 25, 2026
Vulnerability identifier: #VU135157
CSH Severity: Low
CVSS v4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-12490
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass client certificate-based access controls for zone transfers.
The vulnerability exists due to improper access control in the provide-xfr zone transfer authorization logic when handling zone transfer requests over the regular tls-port or regular TCP port. A remote user can request a zone transfer without presenting the required client certificate to bypass client certificate-based access controls for zone transfers.
Exploitation requires matching the other access control conditions of the provide-xfr rule, and the issue applies when tls-auth-xfr-only is not explicitly set to yes.
Affected software
NSD
Fedora
Ubuntu
nsd (Ubuntu package)
nsd
Fedora
Ubuntu
nsd (Ubuntu package)
nsd
How to mitigate CVE-2026-12490
Install security update from vendor's website.
NSD - update to 4.14.3
nsd (Ubuntu package) - addressed in versions 4.1.7-1ubuntu0.1~esm1, 4.1.17-1ubuntu0.1~esm1, 4.1.26-1ubuntu0.1~esm1, 4.3.9-1ubuntu0.1~esm1, 4.8.0-1ubuntu0.1~esm1, 4.14.0-1ubuntu0.1~esm1
nsd - addressed in versions 4.14.3-1.fc43, 4.14.3-1.fc44, 4.15.0-1.el10_3
nsd (Ubuntu package) - addressed in versions 4.1.7-1ubuntu0.1~esm1, 4.1.17-1ubuntu0.1~esm1, 4.1.26-1ubuntu0.1~esm1, 4.3.9-1ubuntu0.1~esm1, 4.8.0-1ubuntu0.1~esm1, 4.14.0-1ubuntu0.1~esm1
nsd - addressed in versions 4.14.3-1.fc43, 4.14.3-1.fc44, 4.15.0-1.el10_3