Vulnerability identifier: #VU46980

Vulnerability risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-25603

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to event channels control structures can be accessed lockless as long as the port is considered to be valid. Such sequence is missing appropriate memory barrier (e.g smp_*mb()) to prevent both the compiler and CPU to re-order access. A malicious guest may be able to cause a hypervisor crash.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Xen: 4.10.0 - 4.14.0

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External links
http://xenbits.xen.org/xsa/advisory-340.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.