Oracle Linux: CVE-2023-6516: ELSA-2024-1781: bind9.16 security update (IMPORTANT) (Multiple Advisories)

To keep its cache database efficient, `named` running as a recursive resolver occasionally attempts to clean up the database. It uses several methods, including some that are asynchronous: a small chunk of memory pointing to the cache element that can be cleaned up is first allocated and then queued for later processing. It was discovered that if the resolver is continuously processing query patterns triggering this type of cache-database maintenance, `named` may not be able to handle the cleanup events in a timely manner. This in turn enables the list of queued cleanup events to grow infinitely large over time, allowing the configured `max-cache-size` limit to be significantly exceeded.
This issue affects BIND 9 versions 9.16.0 through 9.16.45 and 9.16.8-S1 through 9.16.45-S1.
A flaw was found in the `named` application, part of the bind9 package, which uses a cache database to speeds up DNS queries. To maintain its efficiency when running as a recursive name resolver, `named` performs a cache database clean up under certain conditions. This issue may allow an attacker to craft a continuous set of crafted queries, which can induce `named` to trigger the cleanup process with a high frequency, making the internal cleanup items queue to grow indefinitely. This can lead to an uncontrolled memory consumption and resource starvation, potentially making `named` consume all available memory in the host, leading to a Denial of Service of the targeted system.