// For flags

CVE-2021-28692

 

Severity Score

7.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

inappropriate x86 IOMMU timeout detection / handling IOMMUs process commands issued to them in parallel with the operation of the CPU(s) issuing such commands. In the current implementation in Xen, asynchronous notification of the completion of such commands is not used. Instead, the issuing CPU spin-waits for the completion of the most recently issued command(s). Some of these waiting loops try to apply a timeout to fail overly-slow commands. The course of action upon a perceived timeout actually being detected is inappropriate: - on Intel hardware guests which did not originally cause the timeout may be marked as crashed, - on AMD hardware higher layer callers would not be notified of the issue, making them continue as if the IOMMU operation succeeded.

Una detección/manipulación inapropiada del tiempo de espera de la IOMMU x86 Las IOMMUs procesan los comandos emitidos a ellas en paralelo con la operación de la(s) CPU(s) que emiten dichos comandos. En la implementación actual en Xen, la notificación asíncrona de la finalización de dichos comandos no es usada. En su lugar, la CPU emisora espera la finalización de la(s) última(s) orden(es) emitida(s). Algunos de estos bucles de espera intentan aplicar un tiempo de espera para crear un fallo en los comandos demasiado lentos. El curso de acción cuando se detecta un tiempo de espera es inapropiado: - en el hardware de Intel los huéspedes que no causaron originalmente el tiempo de espera pueden ser marcados como bloqueados, - en el hardware de AMD los llamadores de la capa superior no serían notificados del problema, haciéndolos continuar como si la operación de IOMMU tuviera éxito

*Credits: This issue was discovered by Igor Druzhinin and Andrew Cooper of Citrix, and further issues were uncovered by by Jan Beulich of SUSE while trying to fix the first issue.
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
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
  • 2021-06-28 CVE Published
  • 2023-03-08 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-269: Improper Privilege Management
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