Improper Privilege Management Affecting xen package, versions <4.15.0-r3


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-ALPINE316-XEN-2844906
  • published9 Sept 2021
  • disclosed8 Sept 2021

Introduced: 8 Sep 2021

CVE-2021-28701  (opens in a new tab)
CWE-269  (opens in a new tab)

How to fix?

Upgrade Alpine:3.16 xen to version 4.15.0-r3 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:3.16 relevant fixed versions and status.

Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed.

CVSS Scores

version 3.1