Description
The em_sysenter function in arch/x86/kvm/emulate.c in the Linux kernel before 3.18.5, when the guest OS lacks SYSENTER MSR initialization, allows guest OS users to gain guest OS privileges or cause a denial of service (guest OS crash) by triggering use of a 16-bit code segment for emulation of a SYSENTER 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 | 3.16.7-ckt4-2 | — |
| Debian 13 | linux | 3.16.7-ckt4-2 | — |
| Debian 12 | linux | 3.16.7-ckt4-2 | — |
| Debian 7 | linux | 3.2.65-1+deb7u2 | DSA-3170-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | linux | 3.13.0-46.75 | USN-2516-1 |
| Ubuntu 14.04 LTS | linux-lts-utopic | 3.16.0-31.41~14.04.1 | USN-2517-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | perf +18 | 3.10.0-327.el7 | RHSA-2015:2152 |
| RHEL 6 | perf +16 | 2.6.32-573.el6 | RHSA-2015:1272 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | dtrace-modules-3.8.13-68.3.5.el6uek | 0.4.3-4.el6 | ELSA-2015-3053 |
| Oracle Linux 7 | dtrace-modules-3.8.13-68.3.5.el7uek | 0.4.3-4.el7 | ELSA-2015-3053 |
| Oracle Linux 7 | kernel-uek +5 | 3.8.13-68.3.5.el7uek | ELSA-2015-3053 |
| Oracle Linux 7 | perf +11 | 3.10.0-327.el7 | ELSA-2015-2152 |
Advisories 7
- RHSA-2015:2152 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2015:1272 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- USN-2516-1 linux vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3170-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-2517-1 linux-lts-utopic vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- ELSA-2015-2152 Important: kernel security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 24, 2015
- ELSA-2015-3053 Moderate: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jul 29, 2015
References
- USN-2515-1 vendor-advisory
- DSA-3170 vendor-advisory
- 72842 vdb-entry
- [oss-security] 20150127 KVM SYSENTER emulation vulnerability - CVE-2015-0239 mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=1186448
- http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git%3Ba=commit%3Bh=f3747379accba8e95d70cec0eae0582c8c182050
- http://www.oracle.com/technetwork/topics/security/linuxbulletinjan2016-2867209.html
- https://github.com/torvalds/linux/commit/f3747379accba8e95d70cec0eae0582c8c182050
- USN-2514-1 vendor-advisory
- USN-2518-1 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
- http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.18.5
- MDVSA-2015:058 vendor-advisory
- [bk-commits-head] 20150123 KVM: x86: SYSENTER emulation is broken mailing-list
- USN-2517-1 vendor-advisory
- USN-2516-1 vendor-advisory
- RHSA-2015:1272 vendor-advisory
- USN-2513-1 vendor-advisory