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CVE-2021-28701

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.

Published

2021-09-08T14:15:08.547

Last Modified

2024-11-21T06:00:10.450

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.8 (HIGH)

CVSSv2 Vector

AV:L/AC:M/Au:N/C:P/I:P/A:P

  • Access Vector: LOCAL
  • Access Complexity: MEDIUM
  • Authentication: NONE
  • Confidentiality Impact: PARTIAL
  • Integrity Impact: PARTIAL
  • Availability Impact: PARTIAL
Exploitability Score

3.4

Impact Score

6.4

Weaknesses
  • Type: Primary
    CWE-362
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System xen xen ≥ 4.0.0 Yes
Operating System debian debian_linux 11.0 Yes
Operating System fedoraproject fedora 33 Yes
Operating System fedoraproject fedora 34 Yes
Operating System fedoraproject fedora 35 Yes
References