CVE-2016-3159

What it is

The fpu_fxrstor function in arch/x86/i387.c in Xen 4.x does not properly handle writes to the hardware FSW.ES bit when running on AMD64 processors, which allows local guest OS users to obtain sensitive register content information from another guest by leveraging pending exception and mask bits. NOTE: this vulnerability exists because of an incorrect fix for CVE-2013-2076.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. Limited direct impact.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2016-04-13 16:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 00:45 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 3.8 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2016-04-13 16:59 UTC

Last modified

2026-06-17 00:45 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-200 · Information exposure

Record status

Modified

Affected

• Oracle Vm Server 3.3
• Oracle Vm Server 3.4
• Xen ≤ 4.3.4
• Xen ≤ 4.4.4
• Xen ≤ 4.5.3
• Xen ≤ 4.6.1
• Fedoraproject Fedora 22
• Fedoraproject Fedora 23

Attack profile CVSS 3.0 · 3.8

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

Low

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2016-3159.md and follow it. Check whether this project is affected by CVE-2016-3159. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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