Improper Privilege Management Affecting xen package, versions <4.14.3-1~deb11u1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.05% (16th percentile)

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  • Snyk IDSNYK-DEBIAN11-XEN-1569768
  • published26 Aug 2021
  • disclosed27 Aug 2021

Introduced: 26 Aug 2021

CVE-2021-28697  (opens in a new tab)
CWE-269  (opens in a new tab)

How to fix?

Upgrade Debian:11 xen to version 4.14.3-1~deb11u1 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:11 relevant fixed versions and status.

grant table v2 status pages may remain accessible after de-allocation Guest get 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, get de-allocated when a guest switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests from the guest to insert mappings of these pages may result in any of them to become mapped in multiple locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed and perhaps re-used for other purposes.

CVSS Scores

version 3.1