Multiple security vulnerabilities affect NLnet Labs Unbound up to and including version 1.26.1. These include a cache-level side-channel vulnerability that can leak upstream source port information under specific configurations, DNSSEC validation bypasses that can cause trust islands to be treated as insecure, and a performance degradation issue via chained compression pointers. These flaws can lead to cache poisoning, denial of DNS record existence, and degraded resolver performance. A fix is available in version 1.17.1-25.oe2403sp1.