CVEvulnerability

CVE-2021-28697

7.8 HIGH Published 2021-08-27 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-08-27
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.8 HIGH — CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0 ([email protected])
4.6 MEDIUM — AV:L/AC:L/Au:N/C:P/I:P/A:P
Weaknesses
CWE-362

Description

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.

Affected configurations

• xen xen (>= 4.0.0 <= 4.15.0) • fedoraproject fedora 33 • fedoraproject fedora 34 • fedoraproject fedora 35 • debian debian linux 11.0

Related

Weakness · CWE (1)

  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization weakness

References