// For flags

CVE-2021-28698

 

Severity Score

5.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

long running loops in grant table handling In order to properly monitor resource use, Xen maintains information on the grant mappings a domain may create to map grants offered by other domains. In the process of carrying out certain actions, Xen would iterate over all such entries, including ones which aren't in use anymore and some which may have been created but never used. If the number of entries for a given domain is large enough, this iterating of the entire table may tie up a CPU for too long, starving other domains or causing issues in the hypervisor itself. Note that a domain may map its own grants, i.e. there is no need for multiple domains to be involved here. A pair of "cooperating" guests may, however, cause the effects to be more severe.

bucles de larga duración en el manejo de la tabla de concesiones. Con el fin de supervisar adecuadamente el uso de los recursos, Xen mantiene inmaneración sobre las asignaciones de concesiones que un dominio puede crear para asignar concesiones ofrecidas por otros dominios. En el proceso de llevar a cabo determinadas acciones, Xen iteraría sobre todas esas entradas, incluyendo las que ya no están en uso y algunas que pueden haber sido creadas pero nunca usadas. Si el número de entradas para un dominio dado es lo suficientemente grande, esta iteración de toda la tabla puede atar una CPU durante mucho tiempo, no alimentando otros dominios o causando problemas en el propio hypervisor. Tenga en cuenta que un dominio puede asignar sus propias concesiones, es decir, no es necesario que haya varios dominios involucrados aquí. Un par de huéspedes "cooperantes" pueden, sin embargo, causar que los efectos sean más severos.

*Credits: This issue was discovered by Andrew Cooper of Citrix.
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete
* 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-835: Loop with Unreachable Exit Condition ('Infinite Loop')
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"
 >= 3.2.0
Search vendor "Xen" for product "Xen" and version " >= 3.2.0"
-
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