Improper access control in NSD - CVE-2026-18664
Published: August 26, 2026
Vulnerability identifier: #VU145736
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-18664
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass IP-based access control restrictions.
The vulnerability exists due to improper access control in IP range access control handling when comparing IP addresses against configured ranges on little endian systems. A remote attacker can send requests from unintended IP addresses to bypass IP-based access control restrictions.
The issue affects both IPv4 and IPv6 range comparisons.
Affected software
NSD
Fedora
nsd
Fedora
nsd
How to mitigate CVE-2026-18664
Install security update from vendor's website.
NSD - update to 4.15.1
nsd - addressed in versions 4.15.1-1.el9, 4.15.1-1.el10_2, 4.15.1-1.el10_3, 4.15.1-1.el10_4, 4.15.1-1.fc43, 4.15.1-1.fc44, 4.15.1-1.fc45
nsd - addressed in versions 4.15.1-1.el9, 4.15.1-1.el10_2, 4.15.1-1.el10_3, 4.15.1-1.el10_4, 4.15.1-1.fc43, 4.15.1-1.fc44, 4.15.1-1.fc45