If kdcproxy receives a request for a realm which does not have server addresses defined in its configuration, by default, it will query SRV records in the DNS zone matching the requested realm name. This creates a server-side request forgery vulnerability, since an attacker could send a request for a realm matching a DNS zone where they created SRV records pointing to arbitrary ports and hostnames (which may resolve to loopback or internal IP addresses). This vulnerability can be exploited to probe internal network topology and firewall rules, perform port scanning, and exfiltrate data. Deployments where the "use_dns" setting is explicitly set to false are not affected.
https://access.redhat.com/errata/RHSA-2025:22982
https://access.redhat.com/errata/RHSA-2025:21821
https://access.redhat.com/errata/RHSA-2025:21820
https://access.redhat.com/errata/RHSA-2025:21819
https://access.redhat.com/errata/RHSA-2025:21818
https://access.redhat.com/errata/RHSA-2025:21806
https://access.redhat.com/errata/RHSA-2025:21748
https://access.redhat.com/errata/RHSA-2025:21448
https://access.redhat.com/errata/RHSA-2025:21142
https://access.redhat.com/errata/RHSA-2025:21141
https://access.redhat.com/errata/RHSA-2025:21140