The x86/fpu (Floating Point Unit) subsystem in the Linux kernel before 4.13.5, when a processor supports the xsave feature but not the xsaves feature, does not correctly handle attempts to set reserved bits in the xstate header via the ptrace() or rt_sigreturn() system call, allowing local users to read the FPU registers of other processes on the system, related to arch/x86/kernel/fpu/regset.c and arch/x86/kernel/fpu/signal.c.
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.5
https://github.com/torvalds/linux/commit/814fb7bb7db5433757d76f4c4502c96fc53b0b5e
https://source.android.com/security/bulletin/pixel/2018-01-01
Source: MITRE
Published: 2017-10-17
Updated: 2018-01-13
Type: CWE-200
Base Score: 2.1
Vector: AV:L/AC:L/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 3.9
Severity: LOW
Base Score: 5.5
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 1.8
Severity: MEDIUM