The unbound DNS resolver in Red Hat Enterprise Linux 10 contains a vulnerability (CVE-2026-50252) that allows DNS cache poisoning due to predictable UDP source ports. This weakness can be exploited to inject malicious DNS data into the resolver's cache, potentially redirecting users to malicious sites. Red Hat has issued a security advisory (RHSA-2026:68291) and released updated unbound packages (version 1.24.2-7.el10_2.5) that fix this issue across multiple supported architectures and extended update support versions. The advisory rates the impact as moderate and provides detailed update instructions.

Successful exploitation of this vulnerability could allow an attacker to poison the DNS cache of the unbound resolver, potentially causing incorrect DNS responses to be cached and served to clients. This could lead to redirection of users to malicious sites or disruption of DNS resolution. However, the overall severity is rated moderate by Red Hat, indicating a limited but meaningful risk.

Red Hat has released an official security update for unbound in Red Hat Enterprise Linux 10 that addresses this vulnerability. Users should apply the update as described in Red Hat advisory RHSA-2026:68291 and the referenced article https://access.redhat.com/articles/11258. No additional mitigation steps are required beyond applying the official patch.