This security advisory covers multiple vulnerabilities in the Unbound DNS resolver packages used in Red Hat Hardened Images and Red Hat Enterprise Linux 10. The issues include denial of service vulnerabilities via excessive EDNS options (CVE-2026-41292), excessive resource consumption with large DNS resource record sets (CVE-2026-44390), degraded resolution performance in jostle logic (CVE-2026-42534), and cache manipulation through ghost domain names (CVE-2026-40622). Red Hat has released updated RPM packages (version 1.25.1-2.hum1 and 1.24.2-7.el10_2.2) that fix these vulnerabilities across multiple architectures including aarch64 and x86_64. The advisories provide detailed package lists and instructions for applying the updates. No active exploits are known in the wild at this time.

Successful exploitation of these vulnerabilities could lead to denial of service conditions affecting the Unbound DNS resolver, potentially disrupting DNS resolution services. The cache manipulation vulnerability could allow an attacker to influence DNS cache entries, which may impact DNS integrity. These issues affect systems running vulnerable versions of Unbound on Red Hat Hardened Images and Red Hat Enterprise Linux 10. No evidence of active exploitation is reported.

Red Hat has released updated Unbound packages that address these vulnerabilities. Users should apply the provided RPM updates (e.g., unbound-1.25.1-2.hum1, unbound-1.24.2-7.el10_2.2) as soon as possible to remediate the issues. Detailed update instructions and package downloads are available via Red Hat's official advisories at https://access.redhat.com/errata/RHSA-2026:24013 and https://access.redhat.com/errata/RHSA-2026:36320. No additional mitigation steps are indicated by the vendor.