Insufficient verification of data authenticity in Unbound - CVE-2026-42960
Published: May 20, 2026
Vulnerability identifier: #VU131931
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-42960
CWE-ID: CWE-345
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: NLnet Labs
Affected software:
Unbound
Unbound
Detailed vulnerability description
The vulnerability allows a remote attacker to poison Unbound's DNS cache.
The vulnerability exists due to improper cache validation in processing authority and additional section RRSets when handling spoofed DNS replies or fragmented responses. A remote attacker can inject non-NS RRSets accompanied by related address records to poison Unbound's DNS cache.
Exploitation requires the ability to attach malicious records to a reply, such as through packet spoofing or fragmentation attacks.
How to mitigate CVE-2026-42960
Install security update from vendor's website.