Resource Exhaustion Affecting xen package, versions <4.11.4+37-g3263f257ca-1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-DEBIAN10-XEN-1011862
  • published23 Sept 2020
  • disclosed23 Sept 2020

Introduced: 23 Sep 2020

CVE-2020-25601  (opens in a new tab)
CWE-400  (opens in a new tab)

How to fix?

Upgrade Debian:10 xen to version 4.11.4+37-g3263f257ca-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen package and not the xen package as distributed by Debian. See How to fix? for Debian:10 relevant fixed versions and status.

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.

CVSS Scores

version 3.1