CVE-2020-25598

描述

An issue was discovered in Xen 4.14.x. There is a missing unlock in the XENMEM_acquire_resource error path. The RCU (Read, Copy, Update) mechanism is a synchronisation primitive. A buggy error path in the XENMEM_acquire_resource exits without releasing an RCU reference, which is conceptually similar to forgetting to unlock a spinlock. A buggy or malicious HVM stubdomain can cause an RCU reference to be leaked. This causes subsequent administration operations, (e.g., CPU offline) to livelock, resulting in a host Denial of Service. The buggy codepath has been present since Xen 4.12. Xen 4.14 and later are vulnerable to the DoS. The side effects are believed to be benign on Xen 4.12 and 4.13, but patches are provided nevertheless. The vulnerability can generally only be exploited by x86 HVM VMs, as these are generally the only type of VM that have a Qemu stubdomain. x86 PV and PVH domains, as well as ARM VMs, typically don't use a stubdomain. Only VMs using HVM stubdomains can exploit the vulnerability. VMs using PV stubdomains, or with emulators running in dom0, cannot exploit the vulnerability.

如何修補 CVE-2020-25598

要修補 CVE-2020-25598,請將受影響套件升級到下列已修補版本。

• —升級至 4.12.3-r4 或更新版本

CVE-2020-25598 正在被利用嗎?

低 — EPSS 為 0.4%,目前沒有觀察到大規模利用活動。

受影響套件(1)

• >= 4.12.0, < 4.12.3-r4

CVSS 分數

參考連結(1)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2020-25598