CVE-2026-33278

A flaw was discovered in Unbound’s DNSSEC validator can leave it using an invalid memory pointer after certain DS sub-query validations fail due to NSEC3 budget exhaustion. This may cause crashes and could potentially allow arbitrary code execution.

Red Hat Product Security has rated this vulnerability as having an Important impact because an unauthenticated remote adversary can crash the DNS service or potentially achieve code execution with the privileges of the daemon process, rather than being limited to local privileges. In default Red Hat Enterprise Linux and OpenShift environments, Unbound is not enabled by default, limiting exposure to systems explicitly deployed as validating recursive resolvers. Although memory corruption can lead to denial of service or process compromise, high attack complexity and platform memory protections reduce the likelihood of reliable arbitrary code execution.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.