// For flags

CVE-2021-28697

 

Severity Score

7.8
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

Las páginas de estado de grant table v2 pueden seguir siendo accesibles después de la desasignación. Los invitados obtienen acceso permitido a determinadas páginas de memoria de propiedad de Xen. La mayoría de estas páginas permanecen asignadas / asociadas a un huésped durante toda su vida. Las páginas de estado de grant table v2, sin embargo, se desasignan cuando un huésped cambia (de vuelta) de v2 a v1. La liberación de estas páginas requiere que el hypervisor sepa en qué parte del huésped se asignaron estas páginas. El hypervisor rastrea sólo un uso dentro del espacio del huésped, pero las peticiones de carrera del huésped para insertar mapeos de estas páginas pueden resultar en que cualquiera de ellas se mapee en múltiples ubicaciones. Al volver a cambiar de v2 a v1, el huésped retendría el acceso a una página que fue liberada y quizás reusada para otros propósitos.

*Credits: This issue was discovered by Jan Beulich of SUSE.
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-03-18 CVE Reserved
  • 2021-08-27 CVE Published
  • 2023-03-08 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Xen
Search vendor "Xen"
 Xen
Search vendor "Xen" for product "Xen"
 >= 4.0.0 <= 4.15.0
Search vendor "Xen" for product "Xen" and version " >= 4.0.0 <= 4.15.0"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 33
Search vendor "Fedoraproject" for product "Fedora" and version "33"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 35
Search vendor "Fedoraproject" for product "Fedora" and version "35"
-
Affected
Debian
Search vendor "Debian"
 Debian Linux
Search vendor "Debian" for product "Debian Linux"
 11.0
Search vendor "Debian" for product "Debian Linux" and version "11.0"
-
Affected