Chapter 1. Overview of alt-java
Chapter 1. Overview of alt-java Red Hat packages contain a mitigation for the SSB vulnerability in the form of a patch for the java binary. This patch disables an optimization present in x86-64 (Intel and AMD) processors. Disabling that optimization reduces the risk of kernel side-channel attacks, but also reduces CPU performance. Since the patch reduces performance, it has been removed from the java launcher. A new binary alt-java is now available. From the January 2021 Critical Patch Update release (1.8.0 282.b08, 11.0.10.9) onwards, the alt-java binary is included in Red Hat build of OpenJDK 8 and Red Hat build of OpenJDK 11 GA RPM packages. Additional resources For more information about the performance impact of SSB mitigation, see Kernel Side-Channel Attack using Speculative Store Bypass - CVE-2018-3639 on the Red Hat Customer Portal For more information about the java binary patch, see RH1566890 in the Red Hat Bugzilla documentation.