CVE-2021-28701

CVE Details

Release Date:	2021-09-08
Impact:	None	What is this?

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.

See more information about CVE-2021-28701 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	7.8
Vector String:	CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Version:	3.0
Attack Vector:	Local
Attack Complexity:	High
Privileges Required:	Low
User Interaction:	None
Scope:	Changed
Confidentiality Impact:	High
Integrity Impact:	High
Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle VM version 3 (xen)	OVMSA-2021-0033	2021-10-07