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Debian: CVE-2021-28701: xen -- security update

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Debian: CVE-2021-28701: xen -- security update

Severity
4
CVSS
(AV:L/AC:M/Au:N/C:P/I:P/A:P)
Published
09/08/2021
Created
11/04/2022
Added
11/04/2022
Modified
11/04/2022

Description

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.

Solution(s)

  • debian-upgrade-xen

References

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