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Fencer Vulns
high 7.8

CVE-2016-3157 json

The __switch_to function in arch/x86/kernel/process_64.c in the Linux kernel does not properly context-switch IOPL on 64-bit PV Xen guests,…

published 2016-04-12 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-4209

cvss
7.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

The __switch_to function in arch/x86/kernel/process_64.c in the Linux kernel does not properly context-switch IOPL on 64-bit PV Xen guests, which allows local guest OS users to gain privileges, cause a denial of service (guest OS crash), or obtain sensitive information by leveraging I/O port access.

Patch / fix

  • linux Debian 14, Debian 13, Debian 12 4.5.1-1

debian advisories DEBIAN-CVE-2016-3157

  • linux Ubuntu 14.04 LTS 3.13.0-86.130
  • linux Ubuntu 16.04 LTS 4.4.0-22.39
  • linux-raspi2 Ubuntu 16.04 LTS 4.4.0-1010.12
  • linux-lts-wily Ubuntu 14.04 LTS 4.2.0-36.41~14.04.1
  • linux-lts-vivid Ubuntu 14.04 LTS 3.19.0-59.65~14.04.1
  • linux-lts-utopic Ubuntu 14.04 LTS 3.16.0-71.91~14.04.1
  • linux-lts-xenial Ubuntu 14.04 LTS 4.4.0-22.39~14.04.1
  • linux-snapdragon Ubuntu 16.04 LTS 4.4.0-1013.14

ubuntu advisories UBUNTU-CVE-2016-3157

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-3157 updated cvss 7.0

kernel: xen: Privilege escalation on 64-bit Xen PV domains with IO port access privileges (XSA-171)

  • Red Hat Enterprise Linux 5 kernel
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix available
  • Red Hat Enterprise Linux 7 kernel, bpftool
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 perf, kernel, kernel-rt, kernel-alt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-core, kernel-tools, python3-perf, +17 more Red Hat Enterprise MRG 2 kernel-rt, mrg-rt-release, kernel-rt-trace, kernel-rt-vanilla, kernel-rt-firmware
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 7.8 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-264 Permissions, Privileges, and Access Controls

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.