CVE-2019-18425
Fixed in a distro release EPSS 3%
An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.
Products: xen, debian_linux, fedoraproject fedora, opensuse leap
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Alpine 3.10 | xen | 4.12.1-r1 |
| Alpine 3.11 | xen | 4.13.0-r0 |
| Alpine 3.12 | xen | 4.13.0-r0 |
| Alpine 3.13 | xen | 4.13.0-r0 |
| Alpine 3.14 | xen | 4.13.0-r0 |
| Alpine 3.15 | xen | 4.13.0-r0 |
| Alpine 3.16 | xen | 4.13.0-r0 |
| Alpine 3.17 | xen | 4.13.0-r0 |
| Alpine 3.18 | xen | 4.13.0-r0 |
| Alpine 3.19 | xen | 4.13.0-r0 |
| Alpine 3.20 | xen | 4.13.0-r0 |
| Alpine 3.21 | xen | 4.13.0-r0 |
| Alpine 3.22 | xen | 4.13.0-r0 |
| Alpine 3.23 | xen | 4.13.0-r0 |
| Alpine 3.24 | xen | 4.13.0-r0 |
| Alpine 3.8 | xen | 4.10.4-r1 |
| Alpine 3.9 | xen | 4.11.2-r1 |
| Debian 10 | xen | 4.11.3+24-g14b62ab3e5-1~deb10u1 |
| Debian 12 | xen | 4.11.3+24-g14b62ab3e5-1 |
| Debian 13 | xen | 4.11.3+24-g14b62ab3e5-1 |
| Debian 14 | xen | 4.11.3+24-g14b62ab3e5-1 |
| Debian 9 | xen | 4.8.5.final+shim4.10.4-1+deb9u12 |
| SUSE Enterprise Storage 5 | xen | 4.9.4_06-3.59.1 |
| SUSE HPE Helion OpenStack 8 | xen | 4.9.4_06-3.59.1 |
| SUSE Linux Enterprise Desktop 12 SP4 | xen | 4.11.2_04-2.17.1 |
| SUSE Linux Enterprise Module for Basesystem 15 | xen | 4.10.4_06-3.25.1 |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | xen | 4.12.1_04-3.6.1 |
| SUSE Linux Enterprise Module for Server Applications 15 | xen | 4.10.4_06-3.25.1 |
| SUSE Linux Enterprise Module for Server Applications 15 SP1 | xen | 4.12.1_04-3.6.1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | xen | 4.2.5_22-45.36.1 |
| SUSE Linux Enterprise Server 11 SP4-LTSS | xen | 4.4.4_42-61.52.1 |
| SUSE Linux Enterprise Server 12 SP1-LTSS | xen | 4.5.5_28-22.64.1 |
| SUSE Linux Enterprise Server 12 SP2-BCL | xen | 4.7.6_06-43.59.1 |
| SUSE Linux Enterprise Server 12 SP2-LTSS | xen | 4.7.6_06-43.59.1 |
| SUSE Linux Enterprise Server 12 SP3-BCL | xen | 4.9.4_06-3.59.1 |
| SUSE Linux Enterprise Server 12 SP3-LTSS | xen | 4.9.4_06-3.59.1 |
| SUSE Linux Enterprise Server 12 SP4 | xen | 4.11.2_04-2.17.1 |
| SUSE Linux Enterprise Server for SAP Applications 12 SP1 | xen | 4.5.5_28-22.64.1 |
| SUSE Linux Enterprise Server for SAP Applications 12 SP2 | xen | 4.7.6_06-43.59.1 |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | xen | 4.9.4_06-3.59.1 |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | xen | 4.11.2_04-2.17.1 |
| SUSE Linux Enterprise Software Development Kit 12 SP4 | xen | 4.11.2_04-2.17.1 |
| SUSE OpenStack Cloud 7 | xen | 4.7.6_06-43.59.1 |
| SUSE OpenStack Cloud 8 | xen | 4.9.4_06-3.59.1 |
| SUSE OpenStack Cloud Crowbar 8 | xen | 4.9.4_06-3.59.1 |
| Ubuntu 16.04 LTS | xen | no fix |
| Ubuntu 18.04 LTS | xen | no fix |
| openSUSE Leap 15.0 | xen | 4.10.4_06-lp150.2.25.1 |