Resource Exhaustion Affecting xen package, versions <4.14.0-r1


0.0
medium

Snyk CVSS

    Attack Complexity Low
    Availability High

    Threat Intelligence

    EPSS 0.05% (14th percentile)
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NVD
5.5 medium
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SUSE
6.5 medium

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  • Snyk ID SNYK-ALPINE315-XEN-1929298
  • published 24 Sep 2020
  • disclosed 23 Sep 2020

How to fix?

Upgrade Alpine:3.15 xen to version 4.14.0-r1 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 Alpine. See How to fix? for Alpine:3.15 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.