Red Hat Security Advisory: unbound security update

The unbound packages in Red Hat Enterprise Linux 8 provide a validating, recursive, and caching DNS or DNSSEC resolver. Four security issues have been fixed: CVE-2026-41292 (Denial of Service via excessive EDNS options), CVE-2026-40622 (Cache manipulation via 'ghost domain names' attack), CVE-2026-44390 (Denial of Service due to excessive resource consumption with large DNS Resource Record Sets), and CVE-2026-42534 (Denial of Service due to degraded resolution performance in jostle logic). These vulnerabilities could allow denial of service conditions or cache manipulation affecting DNS resolution integrity. Red Hat has released updated packages to address these vulnerabilities.

These vulnerabilities can lead to denial of service conditions impacting DNS resolution availability and performance, and in one case, cache manipulation which could affect DNS response integrity. The issues affect the unbound DNS resolver component in Red Hat Enterprise Linux 8, potentially disrupting DNS services or enabling cache poisoning attacks.

Red Hat has released updated unbound packages for Red Hat Enterprise Linux 8 that address these vulnerabilities. Users should apply the security update as described in the Red Hat advisory RHSA-2026:37282 and the referenced article https://access.redhat.com/articles/11258 to remediate these issues. No additional mitigations are indicated beyond applying the official update.