Resource exhaustion in Unbound - CVE-2026-41292
Published: May 20, 2026
Vulnerability identifier: #VU131926
CSH Severity: Medium
CVSS v4.0: 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/E:U/U:Green
CVE-ID: CVE-2026-41292
CWE-ID: CWE-400
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 cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in EDNS option parsing when handling queries with long lists of EDNS options. A remote attacker can send specially crafted queries with too many EDNS options to cause a denial of service.
Coordinated attacks can degrade service by tying up Unbound threads while internal data structures for the options are being created.
How to mitigate CVE-2026-41292
Install security update from vendor's website.