CVE-2020-25601

 

Published at: - 24-09-2020 12:15

Last modified: - 28-04-2022 08:19

Total changes: - 4

Description

An issue was discovered in Xen through 4.14.x. There is a lack of preemption in evtchn_reset() / evtchn_destroy(). In particular, the FIFO event channel model allows guests to have a large number of event channels active at a time. Closing all of these (when resetting all event channels or when cleaning up after the guest) may take extended periods of time. So far, there was no arrangement for preemption at suitable intervals, allowing a CPU to spend an almost unbounded amount of time in the processing of these operations. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. All Xen versions are vulnerable in principle. Whether versions 4.3 and older are vulnerable depends on underlying hardware characteristics.

Common Vulnerability Scoring System (CVSS)

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

 

Verification logic

 

Reference

• https://xenbits.xen.org/xsa/advisory-344.html
• FEDORA-2020-306b84fd07-Mailing List, Third Party Advisory
• FEDORA-2020-f668e579be-Mailing List, Third Party Advisory
• DSA-4769-Third Party Advisory
• openSUSE-SU-2020:1608-Mailing List, Third Party Advisory
• FEDORA-2020-d46fe34349-Mailing List, Third Party Advisory
• GLSA-202011-06-Third Party Advisory

 

Keywords

NVD

 

CVE-2020-25601

 

CVE

 

Common vulnerabilities & exposures

 

CVSS

 

Common vulnerability scoring system

 

Security

 

Vulnerabilities

 

Exposures