Description
The x86_decode_insn function in arch/x86/kvm/emulate.c in the Linux kernel before 4.8.7, when KVM is enabled, allows local users to cause a denial of service (host OS crash) via a certain use of a ModR/M byte in an undefined instruction.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 4.8.7-1 | — |
| Debian 13 | linux | 4.8.7-1 | — |
| Debian 12 | linux | 4.8.7-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux | 4.4.0-57.78 | USN-3161-1 |
| Ubuntu 16.04 LTS | linux-raspi2 | 4.4.0-1038.45 | USN-3161-3 |
| Ubuntu 16.04 LTS | linux-snapdragon | 4.4.0-1042.46 | USN-3161-4 |
| Ubuntu 14.04 LTS | linux-lts-xenial | 4.4.0-57.78~14.04.1 | USN-3161-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | kernel-rt +10 | 3.10.0-514.10.2.rt56.435.el7 | RHSA-2017:0387 |
| RHEL 7 | perf +18 | 3.10.0-514.10.2.el7 | RHSA-2017:0386 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | dtrace-modules-4.1.12-61.1.27.el6uek | 0.5.3-2.el6 | ELSA-2017-3514 |
| Oracle Linux 7 | dtrace-modules-4.1.12-61.1.27.el7uek | 0.5.3-2.el7 | ELSA-2017-3514 |
| Oracle Linux 7 | kernel-uek +5 | 4.1.12-61.1.27.el7uek | ELSA-2017-3514 |
| Oracle Linux 7 | perf +11 | 3.10.0-514.10.2.el7 | ELSA-2017-0386 |
Advisories 8
- RHSA-2017:0387 Red Hat Security Advisory: kernel-rt security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2017:0386 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- USN-3161-1 linux vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-3161-2 linux-lts-xenial vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3161-3 linux-raspi2 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- USN-3161-4 linux-snapdragon vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- ELSA-2017-0386 Important: kernel security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Mar 2, 2017
- ELSA-2017-3514 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Feb 6, 2017
References
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.8.7
- 94459 vdb-entry
- https://bugzilla.redhat.com/show_bug.cgi?id=1393350
- RHSA-2017:0387 vendor-advisory
- https://github.com/torvalds/linux/commit/d9092f52d7e61dd1557f2db2400ddb430e85937e
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d9092f52d7e61dd1557f2db2400ddb430e85937e
- [oss-security] 20161122 CVE-2016-8630 kernel: kvm: x86: NULL pointer dereference duringinstruction decode mailing-list
- RHSA-2017:0386 vendor-advisory