Input validation error in ISC BIND - CVE-2026-13321
Published: July 23, 2026
Vulnerability identifier: #VU139206
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-13321
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: ISC
Affected software:
ISC BIND
ISC BIND
Detailed vulnerability description
The vulnerability allows a remote attacker to poison the DNS cache and cause authenticated denial-of-service responses.
The vulnerability exists due to improper input validation in DNSSEC NSEC record validation when processing validly signed NSEC records whose next domain name points outside the signer's zone. A remote attacker can craft malicious NSEC records to poison the DNS cache and cause authenticated denial-of-service responses.
Exploitation requires control of any DNSSEC-signed zone.
How to mitigate CVE-2026-13321
Install security update from vendor's website.