CVE-2021-28701 | Date: (C)2021-09-09 (M)2024-02-09 |
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.
CVSS Score and Metrics +CVSS Score and Metrics -CVSS V3 Severity: | CVSS V2 Severity: |
CVSS Score : 7.8 | CVSS Score : 4.4 |
Exploit Score: 1.1 | Exploit Score: 3.4 |
Impact Score: 6.0 | Impact Score: 6.4 |
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CVSS V3 Metrics: | CVSS V2 Metrics: |
Attack Vector: LOCAL | Access Vector: LOCAL |
Attack Complexity: HIGH | Access Complexity: MEDIUM |
Privileges Required: LOW | Authentication: NONE |
User Interaction: NONE | Confidentiality: PARTIAL |
Scope: CHANGED | Integrity: PARTIAL |
Confidentiality: HIGH | Availability: PARTIAL |
Integrity: HIGH | |
Availability: HIGH | |
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