Security advisory: update your JDK (CVE-2026-91403)

On 2026-10-21, OpenJDK published a vulnerability advisory for CVE-2026-91403 (CVSS 9.1), which concerns eight compromised intermediate CA certificates shipped with the JDK. It affects all supported JDK lines: 8, 11, 17, 21, 25 and 27. This is not a Scala issue, but it affects every application running on the JVM, including Scala ones, as well as Scala build tools that use the JDK’s certificates to download dependencies.