RHSA-2026:71453 — Red Hat Security Advisory: OpenShift Container Platform 4.21.35 bug fix and security update

The Red Hat advisory describes bug fixes and security updates for OpenShift Container Platform 4.21.35. It covers an HTML sanitization bypass, multiple denial-of-service (DoS) issues in Go HTTP/2, SSH and MIME components, and issues affecting SSH FIDO/U2F user-presence and key-constraint checks.