CVE-2026-54588: Poweradmin has Host Header Injection in OIDC redirect_uri, SAML ACS/SLO URL, and Logout Redirect Construction. [CRITICAL] CVSS 9.6 Exploit Intelligence — Recent CVEs / 23h Poweradmin is a web-based DNS administration tool for PowerDNS server. Versions prior to 4.2.4 and 4.3.3 use the attacker-controlled `HTTP_HOST` request header as the authoritative source for building callback URLs in its OIDC, SAML, and logout authentication flows without any validation. An unauthe