CVE-2019-18425
描述
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.
如何修補 CVE-2019-18425
要修補 CVE-2019-18425,請將受影響套件升級到下列已修補版本。
- —升級至 4.12.1-r1 或更新版本
- —升級至 4.11.3+24-g14b62ab3e5-1 或更新版本
CVE-2019-18425 正在被利用嗎?
低 — EPSS 為 2.5%,目前沒有觀察到大規模利用活動。
受影響套件(2)
- from 0, < 4.12.1-r1
- from 0, < 4.11.3+24-g14b62ab3e5-1
CVSS 分數
| 來源 | 版本 | 嚴重程度 | 向量 |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |