Description
The xrstor function in arch/x86/xstate.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.
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 | xen | 4.8.0~rc3-1 | — |
| Debian 13 | xen | 4.8.0~rc3-1 | — |
| Debian 12 | xen | 4.8.0~rc3-1 | — |
| Debian 8 | xen | 4.4.1-9+deb8u5 | DSA-3554-1 |
| Debian 7 | xen | 4.1.6.lts1-1 | DLA-571-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | xen | 4.6.0-1ubuntu4.1 | — |
| Ubuntu 14.04 LTS | xen | 4.4.2-0ubuntu0.14.04.6 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | xen | 4.5.3_08-17.1 | SUSE-SU-2016:2093-1 |
| SLES 12 | xen | 4.4.4_04-22.22.2 | SUSE-SU-2016:2533-1 |
| SLES 11 SP4 | xen | 4.4.4_07-37.1 | SUSE-SU-2016:2100-1 |
| SLES 11 SP3 | xen | 4.2.5_21-27.1 | SUSE-SU-2016:2725-1 |
| SLES 11 SP2 | xen | 4.1.6_08-29.1 | SUSE-SU-2016:2528-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | xen | 4.5.3_08-17.1 | SUSE-SU-2016:2093-1 |
| SLES for SAP 12 | xen | 4.4.4_04-22.22.2 | SUSE-SU-2016:2533-1 |
| SLES for SAP 11 SP4 | xen | 4.4.4_07-37.1 | SUSE-SU-2016:2100-1 |
| SUSE OpenStack Cloud 5 | xen | 4.2.5_21-27.1 | SUSE-SU-2016:2725-1 |
| SUSE Manager Proxy 2.1 | xen | 4.2.5_21-27.1 | SUSE-SU-2016:2725-1 |
| SUSE Manager 2.1 | xen | 4.2.5_21-27.1 | SUSE-SU-2016:2725-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | xen | 4.2.5_21-27.1 | SUSE-SU-2016:2725-1 |
Advisories 7
- DLA-571-1 xen - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3554-1 xen - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:2528-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2533-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2725-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2100-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2093-1 Security update for xen SUSE / openSUSE Security Updates · Feb 4, 2026
References
- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- FEDORA-2016-5f196e4e4a vendor-advisory
- 85714 vdb-entry
- http://xenbits.xen.org/xsa/xsa172-4.3.patch
- http://xenbits.xen.org/xsa/advisory-172.html
- FEDORA-2016-e5432ca977 vendor-advisory
- http://xenbits.xen.org/xsa/xsa172.patch
- 1035435 vdb-entry
- http://support.citrix.com/article/CTX209443
- DSA-3554 vendor-advisory