CVEvulnerability

CVE-2021-28701

7.8 HIGH Published 2021-09-08 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-09-08
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.8 HIGH — CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS 2.0 ([email protected])
4.4 MEDIUM — AV:L/AC:M/Au:N/C:P/I:P/A:P
Weaknesses
CWE-362

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.

Affected configurations

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

Related

Weakness · CWE (1)

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

References