// For flags

CVE-2021-4093

kernel: KVM: SVM: out-of-bounds read/write in sev_es_string_io

Severity Score

8.8
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.

Se ha encontrado un fallo en el código de AMD de KVM para soportar la Virtualización Segura Encriptada-Estado Encriptado (SEV-ES). Un huésped de KVM que use SEV-ES puede desencadenar lecturas y escrituras fuera de límites en el núcleo anfitrión por medio de un VMGEXIT malicioso para una instrucción de E/S de cadena (por ejemplo, outs o ins) usando el motivo de salida SVM_EXIT_IOIO. Este problema resulta en un bloqueo de todo el sistema o en un potencial escenario de escape del huésped al host

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-12-10 CVE Reserved
  • 2022-02-03 CVE Published
  • 2023-09-11 EPSS Updated
  • 2024-08-03 CVE Updated
  • 2024-08-03 First Exploit
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-125: Out-of-bounds Read
  • CWE-787: Out-of-bounds Write
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
 Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
 >= 5.11 < 5.14.16
Search vendor "Linux" for product "Linux Kernel" and version " >= 5.11 < 5.14.16"
-
Affected
Redhat
Search vendor "Redhat"
 Enterprise Linux
Search vendor "Redhat" for product "Enterprise Linux"
 8.0
Search vendor "Redhat" for product "Enterprise Linux" and version "8.0"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
 Fedora
Search vendor "Fedoraproject" for product "Fedora"
 35
Search vendor "Fedoraproject" for product "Fedora" and version "35"
-
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 20.04
Search vendor "Canonical" for product "Ubuntu Linux" and version "20.04"
lts
Affected
Canonical
Search vendor "Canonical"
 Ubuntu Linux
Search vendor "Canonical" for product "Ubuntu Linux"
 21.10
Search vendor "Canonical" for product "Ubuntu Linux" and version "21.10"
-
Affected