Improper Handling of Exceptional Conditions Affecting xen package, versions <4.13.1-r4


0.0
medium

Snyk CVSS

    Attack Complexity Low
    Scope Changed
    Availability High

    Threat Intelligence

    EPSS 0.05% (13th percentile)
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NVD
6.5 medium
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SUSE
6.5 medium

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  • Snyk ID SNYK-ALPINE314-XEN-1308488
  • published 21 Jul 2020
  • disclosed 7 Jul 2020

How to fix?

Upgrade Alpine:3.14 xen to version 4.13.1-r4 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:3.14 relevant fixed versions and status.

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a host OS crash because of incorrect error handling in event-channel port allocation. The allocation of an event-channel port may fail for multiple reasons: (1) port is already in use, (2) the memory allocation failed, or (3) the port we try to allocate is higher than what is supported by the ABI (e.g., 2L or FIFO) used by the guest or the limit set by an administrator (max_event_channels in xl cfg). Due to the missing error checks, only (1) will be considered an error. All the other cases will provide a valid port and will result in a crash when trying to access the event channel. When the administrator configured a guest to allow more than 1023 event channels, that guest may be able to crash the host. When Xen is out-of-memory, allocation of new event channels will result in crashing the host rather than reporting an error. Xen versions 4.10 and later are affected. All architectures are affected. The default configuration, when guests are created with xl/libxl, is not vulnerable, because of the default event-channel limit.