Redhat » Enterprise Linux Server : Security Vulnerabilities, CVEs, Published In 2009 (Information Leak)

arch/x86/ia32/ia32entry.S in the Linux kernel before 2.6.31.4 on the x86_64 platform does not clear certain kernel registers before a return to user mode, which allows local users to read register values from an earlier process by switching an ia32 process to 64-bit mode.